The real function of digital dollars is not to replace money, but to connect markets that were never designed to speak to one another

Stablecoins are usually introduced as a simple idea: digital tokens designed to maintain a fixed value, most often one U.S. dollar.

That definition is technically correct. It is also economically incomplete.

Calling a stablecoin “digital money” makes it sound like a new version of cash. It suggests that the token’s primary purpose is to pay for groceries, settle a restaurant bill, or replace the balance in a checking account.

In practice, most stablecoins do something far more structural.

They move dollar-denominated value between cryptocurrency exchanges, decentralized trading protocols, lending markets, wallets, custodians, banks, and government-debt markets. They allow assets native to blockchains to interact with financial value that still originates in the conventional monetary system.

Their most important role is therefore not monetary substitution.

It is interconnection.

A stablecoin is best understood as a piece of market plumbing: a privately issued instrument that carries dollar value through digital markets whose trading hours, settlement architecture, custody models, and geographic boundaries differ radically from those of traditional finance.

The pipes are largely invisible when they work. Yet they determine where liquidity can travel, how quickly collateral can move, which institutions can participate, and where pressure accumulates when confidence begins to crack.

This distinction matters because a market should not be judged merely by the labels attached to its instruments. It should be judged by the flows those instruments make possible.

Stablecoins may resemble money at the surface. Underneath, they behave more like a financial transmission system.

Large Transaction Volumes Do Not Necessarily Mean a Large Payment Economy

Stablecoin statistics can appear astonishing.

By early April 2026, the global stablecoin market had grown to roughly $315 billion in outstanding value. The Bank for International Settlements estimated that stablecoin transfer volume reached approximately $35 trillion in 2025.

At first glance, a number that large seems to suggest the emergence of a global payment network competing with commercial banks, card companies, and central bank money.

But aggregate transfer volume can be deceptive.

The same token may move repeatedly between exchanges, wallets, trading protocols, liquidity pools, market makers, custodians, and automated contracts. A single economic position can generate multiple blockchain transfers as it is created, collateralized, hedged, rebalanced, liquidated, and settled.

Not every transfer represents a person purchasing a product or a business paying a supplier.

Many transfers are internal movements within the machinery of digital-asset markets.

Research by the BIS has found that blockchain data can overstate payment activity because a single transaction may bundle several operations together. Trading, lending, arbitrage, liquidity management, and settlement can appear on a public ledger as if they were ordinary payments, even when no conventional buyer and seller are involved.

The BIS estimated that payment-related stablecoin flows represented only a small fraction of total transfer volume in 2025.

This does not make stablecoins economically insignificant. It makes them significant in a different way.

Their scale is not primarily evidence that consumers have abandoned bank deposits for blockchain wallets. It is evidence that digital-asset markets require an enormous amount of dollar-like liquidity to function.

That liquidity circulates rapidly because it is being used as trading capital, collateral, settlement inventory, and a temporary refuge from volatile assets.

Stablecoins are not merely being spent.

They are being routed.

Two Financial Economies, One Connector

Modern finance increasingly operates across two overlapping but architecturally different environments.

The first is the conventional financial system. It includes commercial banks, central banks, securities markets, payment processors, money-market funds, custodians, and government-debt markets. Transactions are processed through regulated institutions, account-based ledgers, established legal frameworks, and scheduled settlement systems.

The second is the blockchain-based financial system. It includes centralized cryptocurrency exchanges, decentralized exchanges, lending protocols, smart contracts, tokenized assets, self-custodied wallets, and automated market makers. These markets operate continuously, settle through distributed networks, and can transfer assets across borders without following ordinary banking hours.

Neither system is completely isolated from the other.

Crypto markets still require fiat currency. Investors need a way to enter and exit. Traders need a stable unit in which to price risk. Lending protocols need collateral that does not fluctuate as violently as Bitcoin or Ether. Exchanges need settlement assets that can move at any hour without waiting for a bank wire.

Traditional finance, meanwhile, increasingly interacts with tokenized instruments, digital custodians, blockchain settlement systems, and institutions that operate across both environments.

Stablecoins occupy the junction.

They take value recognized by the conventional financial system and reproduce it as a transferable blockchain token. In the other direction, they give holders of blockchain assets a route back toward bank deposits, cash equivalents, and other traditional financial instruments.

They are not the destination.

They are the connector between destinations.

This is why the market-plumbing metaphor is more useful than the digital-cash metaphor. A pipe does not create the water it carries. It determines how the water moves, where it can go, and what happens when the pressure exceeds the system’s capacity.

Stablecoins do not create the dollar’s value. They transport claims tied to that value through a different technological environment.

The Dollar Was Not Replaced. It Was Repackaged.

The overwhelming majority of stablecoins are denominated in U.S. dollars.

That fact is easy to overlook because stablecoins are often presented as part of a technological rebellion against the established financial order. Their imagery emphasizes decentralization, borderless networks, programmable money, and independence from banks.

Yet the dominant stablecoin ecosystem has not displaced the dollar.

It has extended the dollar into blockchain markets.

This is a crucial distinction.

A dollar-backed stablecoin does not establish a new monetary standard. It imports an existing standard into a digital environment. The token may move through decentralized infrastructure, but its unit of account still depends on the credibility, liquidity, and global familiarity of the U.S. dollar.

In that sense, stablecoins are less a rejection of dollar dominance than a new distribution channel for it.

The technology is novel. The monetary hierarchy is not.

A trader in Asia, a lending protocol running on a public blockchain, and a market maker operating across several exchanges can all use the same dollar-denominated token without directly holding a U.S. bank account for each transaction.

That convenience expands the functional reach of the dollar.

The result is a paradox.

Blockchain networks were built in part to reduce dependence on centralized monetary institutions. Yet their largest liquid markets increasingly rely on tokens whose stability ultimately depends on bank accounts, government securities, regulated custodians, redemption policies, and the credibility of dollar-based financial infrastructure.

The surface is decentralized.

The foundation often is not.

Every Fiat-Backed Stablecoin Has Two Floors

A fiat-backed stablecoin has a two-story structure.

The upper floor is the token layer. This is the visible part of the system: the blockchain, wallet balances, smart contracts, decentralized exchanges, lending protocols, and transfers between addresses.

The lower floor is the reserve layer. This includes bank deposits, Treasury bills, repurchase agreements, money-market instruments, custodial arrangements, legal entities, redemption procedures, compliance systems, and relationships with traditional financial institutions.

Users interact mainly with the upper floor.

Confidence depends largely on the lower one.

When someone receives one unit of a dollar-backed stablecoin, the token itself is not a physical dollar and usually is not a direct deposit at a central bank. It is a privately issued claim whose value depends on the issuer’s ability and willingness to redeem it, directly or indirectly, for one dollar.

That promise is supported by a reserve portfolio.

The quality of the promise therefore depends on several questions.

What assets are held in reserve?

Where are they held?

Who has legal title to them?

How liquid are they during periods of stress?

Are they segregated from the issuer’s operating assets?

How frequently are reserve reports produced?

Who verifies them?

Which customers are permitted to redeem directly?

How quickly must redemption requests be processed?

Can redemptions be suspended?

What happens if a banking partner fails?

What happens if regulators freeze part of the reserve?

A stablecoin can appear simple at the token layer while remaining highly complex at the reserve layer.

The blockchain may provide real-time visibility into token movements. It does not automatically provide real-time certainty about the assets supporting those tokens.

This is one reason transparency reports, reserve attestations, custody structures, and redemption terms matter more than branding.

A stablecoin is only as stable as the weakest link between the token and the asset to which it claims to be tied.

The Peg Is Defended by the Road Back to One Dollar

Stablecoin stability is often described as if it were a property of code.

For fiat-backed stablecoins, it is more accurately a property of redemption.

The key mechanism is arbitrage.

Suppose a stablecoin trades below one dollar on the secondary market. A qualified participant may buy the token at a discount, redeem it with the issuer for one dollar, and capture the difference.

That buying pressure can pull the market price back toward the peg.

If the token trades above one dollar, an authorized participant may create new tokens by depositing dollars with the issuer, sell those tokens at the higher market price, and expand supply until the premium narrows.

This mechanism sounds automatic, but it is not available equally to everyone.

Direct redemption may be restricted to verified institutional customers, approved businesses, or users who meet minimum transaction thresholds. Other holders may have to sell through an exchange rather than redeem with the issuer.

That creates two distinct paths back to the dollar.

The first is the primary redemption channel between the issuer and authorized participants.

The second is the secondary-market channel used by ordinary holders.

The peg is strongest when both channels function smoothly.

It becomes more fragile when exchanges lose liquidity, banks stop processing transfers, market makers retreat, redemption requests are delayed, or access to the primary channel becomes uncertain.

This is why the most important question during a stablecoin crisis is not simply whether the reserve assets exist.

The question is whether they can be converted into cash quickly enough, through functioning institutions, while holders are attempting to exit.

A reserve can be solvent on paper and still become difficult to mobilize under stress.

The peg is not maintained by confidence alone.

It is maintained by a credible return path.

Centralized Exchanges Use Stablecoins as Settlement Inventory

On centralized cryptocurrency exchanges, stablecoins frequently function as trading pairs, settlement assets, and temporary stores of value.

A trader who sells Bitcoin does not always exit into a bank account. The proceeds may remain on the exchange as a stablecoin balance, ready to be deployed into another asset.

This reduces friction.

Bank transfers can be slow, limited by business hours, restricted by jurisdiction, or expensive across borders. Stablecoins allow traders to move value between supported platforms and wallets without repeatedly converting through the banking system.

They also provide exchanges with a common quote currency.

Instead of maintaining deep markets against dozens of national currencies, an exchange can list assets against a widely recognized dollar-denominated token. That concentrates liquidity and simplifies pricing.

In this environment, the stablecoin is not primarily a consumer-payment instrument.

It is inventory.

It sits inside the exchange ecosystem as deployable capital, waiting to be traded, withdrawn, lent, pledged, or moved elsewhere.

The distinction resembles the difference between money in a household checking account and cash held by a securities dealer. Both are denominated in dollars, but their economic roles are not identical.

One finances daily life.

The other keeps markets functioning.

Decentralized Exchanges Turn Stablecoins Into Liquidity Infrastructure

On decentralized exchanges, stablecoins serve a different but related function.

A decentralized exchange does not ordinarily maintain a traditional order book managed by a central operator. Many use automated market makers, where users supply pairs of assets to liquidity pools and trades are executed according to formulas embedded in smart contracts.

Stablecoins are especially valuable in this structure because they provide a relatively stable side of a trading pair.

A liquidity pool might contain a stablecoin and Ether, two different stablecoins, or a stablecoin and a tokenized financial asset.

These pools allow traders to exchange assets without waiting for a centralized intermediary to match buyers with sellers.

Stablecoins therefore become part of the exchange mechanism itself.

They are not merely held by users. They are deposited into programmable pools, routed through smart contracts, used to price other assets, and distributed across networks in search of fees and yield.

The apparent simplicity of the dollar peg can conceal substantial complexity beneath the surface.

A token may be moved through multiple protocols, wrapped for use on another network, deposited as collateral, supplied to a liquidity pool, or incorporated into an automated strategy.

Each additional layer introduces new dependencies.

The issuer may remain solvent while a bridge fails.

The token may remain redeemable while a smart contract is exploited.

A liquidity pool may become imbalanced even though the underlying reserves remain intact.

The plumbing does not consist of one pipe.

It is a maze of valves, adapters, reservoirs, and pressure points.

DeFi Uses Stablecoins as Credit Units

Stablecoins are also central to decentralized lending.

In many DeFi protocols, users deposit crypto assets as collateral and borrow stablecoins against them. Others supply stablecoins to lending pools in exchange for interest.

This gives the stablecoin several simultaneous roles.

It acts as the borrowed asset.

It acts as the unit in which debt is measured.

It may act as collateral in another protocol.

It may be deposited into a liquidity pool.

It may be transferred into a different blockchain network.

It may be used to purchase another asset without closing the original collateral position.

This creates a chain of financial relationships that resembles traditional secured lending, margin finance, and collateral transformation, but with much of the process executed automatically through smart contracts.

Liquidation is a central feature.

When the value of a borrower’s collateral falls below the protocol’s required threshold, the position may be liquidated automatically. Collateral is sold or transferred so that the debt can be repaid.

The stablecoin is therefore not merely a neutral token circulating through the system.

It is often the measuring stick by which solvency is judged.

That creates reflexive dynamics.

When crypto prices fall, collateral ratios deteriorate. Liquidations increase. Borrowers may rush to acquire stablecoins to repay debt. Liquidity pools can shift rapidly. Interest rates can spike. Market makers may widen spreads.

A token designed to remain stable can become the center of an unstable scramble for liquidity.

Its price may barely move while the surrounding market experiences severe stress.

That is another reason price stability alone is an incomplete measure of systemic importance.

A pipe can remain physically intact while the pressure inside it becomes dangerous.

The Reserve Layer Connects Stablecoins to Treasury Markets

The reserve portfolios backing major fiat-based stablecoins commonly include cash, bank deposits, short-term government securities, repurchase agreements, and money-market instruments.

As the stablecoin market grows, those reserve portfolios become economically significant.

A large issuer may become a substantial buyer of short-dated government debt. When demand for stablecoins rises, the issuer receives new funds and invests them in eligible reserve assets. When redemptions surge, assets may need to mature, be sold, or be converted into cash.

Stablecoin growth can therefore influence demand for Treasury bills and other highly liquid instruments.

This does not mean stablecoin issuers control government-debt markets. It means they have become another class of cash-management institution operating within those markets.

Their behavior resembles, in certain respects, that of money-market funds.

Both take in funds from investors or users.

Both invest heavily in liquid short-term assets.

Both promise relatively stable value.

Both depend on confidence in the quality and accessibility of their portfolios.

Both can become channels through which large inflows and outflows affect short-term funding markets.

The comparison is not exact. Stablecoins differ in legal structure, technology, redemption rights, distribution, and regulatory treatment.

But the resemblance is important enough that regulators increasingly focus on reserve composition, maturity, custody, liquidity, and redemption timing.

The more stablecoins grow, the less credible it becomes to describe them as a financial world separate from traditional markets.

Their tokens may circulate on blockchains.

Their reserves remain deeply embedded in the existing financial system.

Stablecoins Do Not Eliminate Banks

Stablecoins are sometimes presented as a way to remove banks from finance.

In reality, most fiat-backed stablecoins depend heavily on banks.

Issuers need institutions to hold cash, process incoming and outgoing payments, maintain accounts, support redemptions, and connect to domestic and international payment systems.

Users need banking access to convert between fiat currency and tokens.

Exchanges need banking partners.

Custodians need settlement relationships.

Market makers need reliable channels through which they can move capital between token markets and traditional accounts.

Even when reserves are invested primarily in government securities, cash flows still move through regulated financial institutions.

This creates concentration risk.

If only a small number of banks are willing or able to serve stablecoin issuers, operational pressure accumulates around those relationships. The failure, restriction, or withdrawal of one banking partner can disrupt minting and redemption even when the issuer’s overall reserve portfolio remains sound.

The system may be distributed at the blockchain layer while concentrated at the banking layer.

That is not necessarily a fatal weakness.

It is simply a dependency that must be acknowledged.

A market cannot be understood by examining only the component that users can see.

Regulation Is About Designing the Valves

Stablecoin regulation is sometimes discussed as if governments were deciding whether these tokens should be recognized as “real money.”

That framing misses the practical objective.

Regulators are designing the valves.

They are determining who may issue stablecoins, which assets may support them, how reserves must be held, who can redeem, how quickly redemption must occur, what disclosures are required, how customer assets are protected, and when transactions may be frozen or rejected.

In the United States, the GENIUS Act established a federal framework for payment stablecoins in 2025. Its implementation has required regulators to translate broad legislative principles into operational rules involving reserves, capital, liquidity, custody, redemption, risk management, and supervision.

In the European Union, the Markets in Crypto-Assets framework created specific categories and obligations for asset-referenced and electronic-money tokens. It also placed significant issuers under enhanced oversight and clarified that stablecoin activity does not exist outside the broader architecture of payment and financial regulation.

The United Kingdom has pursued a framework that distinguishes stablecoins used at systemic scale from ordinary crypto assets. Its policy direction emphasizes high-quality backing assets, central bank deposits, liquidity arrangements, redemption rights, and limits intended to reduce financial-stability risks during the transition.

Japan classifies qualifying fiat-linked stablecoins as electronic payment instruments and restricts issuance to regulated entities such as banks, funds-transfer service providers, and trust companies. Intermediaries must operate within registration, custody, anti-money-laundering, and transfer-information requirements.

The details differ across jurisdictions.

The direction is remarkably consistent.

Authorities are not primarily trying to decide whether a blockchain token looks futuristic.

They are asking whether the financial claim beneath it is credible, liquid, supervised, and legally enforceable.

The central regulatory question is not, “Is this token money?”

It is, “What happens when everyone wants their money back?”

Compliance Controls Are Part of the Architecture

Stablecoins can move between self-custodied wallets, decentralized protocols, centralized exchanges, and regulated financial institutions.

That mobility makes them useful.

It also makes them attractive for sanctions evasion, fraud, money laundering, ransomware payments, and other forms of illicit finance.

As a result, many major fiat-backed stablecoins contain centralized control mechanisms.

Issuers may be able to freeze addresses, block transfers, burn tokens, deny redemptions, or cooperate with law-enforcement requests.

These capabilities create an uncomfortable contradiction.

A token may circulate through a public and permissionless blockchain while remaining subject to centralized intervention by its issuer.

From one perspective, this undermines the ideal of censorship-resistant money.

From another, it is a necessary condition for regulatory acceptance, banking access, and integration with mainstream financial institutions.

Both interpretations are valid because they refer to different layers.

The transfer network may be decentralized.

The liability is not.

A private issuer has promised to honor a claim tied to fiat currency. That issuer exists within a legal jurisdiction, depends on regulated counterparties, and can be compelled to comply with court orders and sanctions regimes.

Users who treat every blockchain asset as equally resistant to intervention misunderstand the structure.

Ownership of a private key may give a person technical control over an address.

It does not guarantee that the asset associated with that address will remain transferable or redeemable.

The distinction between control of the wallet and control of the financial claim is essential.

Stability Can Fail in More Than One Place

Stablecoin risk is often reduced to a single question: Will the token hold its one-dollar peg?

That question is important, but it is not enough.

Failure can occur at several different layers.

The reserve portfolio can lose value.

A banking partner can fail.

Redemptions can be suspended.

The issuer can become insolvent.

A custodian can lose access to assets.

A blockchain can become congested.

A bridge can be exploited.

A smart contract can fail.

A decentralized exchange can lose liquidity.

A centralized exchange can block withdrawals.

A government can impose sanctions.

A wallet provider can stop supporting the token.

A token may still trade near one dollar in one venue while becoming difficult to transfer or redeem elsewhere.

Conversely, a temporary market-price deviation may occur even when the reserve assets remain sufficient, simply because liquidity has fragmented and arbitrage channels are not functioning efficiently.

This is why stablecoin analysis must distinguish among price risk, liquidity risk, credit risk, operational risk, legal risk, technological risk, and redemption risk.

A one-dollar market price is not proof that every layer is healthy.

It is only the most visible gauge on the control panel.

The Difference Between Fiat-Backed and Algorithmic Stability

Not all stablecoins rely on the same mechanism.

Fiat-backed stablecoins seek stability through reserves and redemption. Their central promise is that token supply is supported by identifiable financial assets and can be exchanged back into fiat currency under specified conditions.

Crypto-collateralized stablecoins are supported by digital assets deposited into smart contracts, often at values greater than the stablecoins issued against them. Their stability depends on collateral ratios, liquidation systems, oracle prices, and the liquidity of the underlying crypto assets.

Algorithmic stablecoins attempt to maintain a target price through incentives, token supply adjustments, linked assets, or market-based stabilization mechanisms rather than fully liquid fiat reserves.

These models should not be treated as interchangeable.

The word “stablecoin” describes an intended price behavior, not a uniform balance-sheet structure.

A token backed by Treasury bills and bank deposits has a different risk profile from one backed by volatile crypto collateral. Both differ profoundly from a token whose stability depends on confidence in an algorithmic relationship.

The name is the same.

The plumbing is not.

Cross-Chain Transfers Add Another Layer of Dependency

Stablecoins often exist on multiple blockchain networks.

Moving a token from one network to another may involve a bridge, an issuer-operated transfer protocol, or a wrapped representation of the original asset.

These mechanisms are not equivalent.

Traditional bridges may lock tokens on one network and issue a corresponding wrapped asset on another. The user then depends on the security of the bridge, the custody of the locked tokens, and the integrity of the wrapped representation.

Issuer-operated systems may burn tokens on the source network and mint equivalent tokens on the destination network. This can reduce reliance on externally managed liquidity pools, but it still depends on the issuer’s infrastructure, message-verification system, and supported networks.

Cross-chain mobility increases usefulness.

It also expands the number of places where failure can occur.

A stablecoin may be fully backed at the issuer level while a specific bridged version trades at a discount because users doubt the bridge’s solvency or security.

When analyzing a stablecoin position, one must therefore ask not only which token is being held, but also which version of the token, on which network, under which issuance or bridging mechanism.

The label may look identical across interfaces.

The legal and technical claims may not be.

Stablecoins Are Becoming a Settlement Layer for Machines

The next major expansion of stablecoin use may not come from human consumers.

It may come from software.

AI agents, automated trading systems, smart contracts, logistics platforms, data marketplaces, and autonomous services need a way to exchange value without relying on a human to approve every transaction.

Traditional banking systems are poorly suited to continuous machine-to-machine commerce. Accounts require identity checks, interfaces may not support granular automated payments, cross-border settlement can be slow, and operating hours remain tied to institutional schedules.

Stablecoins offer several properties that software can use directly.

They are programmable.

They can settle continuously.

They can move in small units.

They can be integrated into smart contracts.

They can be transferred between addresses without requiring a new bank instruction for every payment.

They can be used as collateral or held temporarily by automated systems.

This does not mean AI agents will be given unrestricted wallets and allowed to spend freely.

In practice, machine payments will require permissions, spending limits, identity frameworks, compliance checks, audit trails, revocation mechanisms, and human-defined objectives.

Yet the underlying compatibility is clear.

Stablecoins turn dollar-denominated value into an object that software can route.

For human users, that may look like a more convenient payment tool.

For autonomous systems, it can function as an operating resource.

An AI agent purchasing computing capacity, paying for data, compensating another agent, posting collateral, or settling a microtransaction does not need philosophical certainty about whether the token is “money.”

It needs an asset that the next machine will accept.

This may become one of the most consequential aspects of stablecoin infrastructure.

Humans tend to think of money through institutions, accounts, and social conventions.

Software thinks in terms of executable permissions.

The Most Important Question Is Where the Claim Ends

A stablecoin can pass through dozens of addresses and protocols while appearing unchanged.

The token symbol remains the same.

The market price remains close to one dollar.

The interface displays a familiar balance.

But the economic claim beneath that balance may be moving through a long chain of dependencies.

The issuer depends on custodians and banks.

The reserve portfolio depends on financial markets.

The exchange depends on liquidity providers.

The bridge depends on validators or message systems.

The lending protocol depends on collateral values and price oracles.

The wallet depends on network access.

The user depends on the ability to transfer, sell, or redeem.

Each layer can work perfectly until the moment another layer fails.

That does not make stablecoins inherently defective.

All financial instruments depend on infrastructure.

A bank deposit depends on the bank, payment networks, central bank liquidity, deposit-insurance rules, legal institutions, and government credibility. A money-market fund depends on custodians, securities markets, asset managers, and redemption procedures.

Stablecoins are not unusual because they have dependencies.

They are unusual because those dependencies cross several financial and technological systems at once.

They connect public blockchains with private issuers.

They connect self-custody with centralized compliance.

They connect decentralized lending with government-debt markets.

They connect automated software with human law.

They connect twenty-four-hour trading with institutions still organized around banking days.

That is why the market-plumbing framework is so useful.

It shifts attention away from slogans and toward structure.

Instead of asking whether stablecoins are the future of money, ask what they connect.

Instead of asking whether a token is decentralized, ask which layer remains centralized.

Instead of asking whether the price is one dollar, ask how the holder can obtain that dollar.

Instead of asking whether transaction volume is large, ask what economic activity produced it.

Instead of asking whether reserves exist, ask whether they are liquid, segregated, accessible, and protected under stress.

Instead of asking whether the blockchain is secure, ask where the claim leaves the blockchain and enters the legal system.

Stablecoins are not replacing the financial system from the outside.

They are being installed inside it.

They are becoming valves between markets, adapters between technologies, and reservoirs of dollar liquidity for digital finance.

Most users will never see the entire network.

They will see a token, a price, and a balance.

But beneath that quiet interface lies a sprawling machine of banks, Treasury securities, custodians, smart contracts, exchanges, regulators, arbitrageurs, and redemption channels.

The token is merely the visible handle.

The real system is the plumbing behind it.