IRC 2024 Shut-Off Valves: Where Individual Fixture Valves Are Required

Quick Answer

Under IRC 2024 Section P2903.9.1, a shut-off valve is required on the supply to every plumbing fixture in a residential building. This includes toilets, lavatories, kitchen sinks, dishwashers, washing machine supply connections, and any other fixture that connects to the water supply. The valve must be accessible without removing or cutting through any permanent construction — it cannot be buried in a wall or under a floor without an access panel.

Under IRC 2024, ball valves and angle stops (also called angle supply valves) are the most common types used. Separate valves on hot and cold supplies are required wherever both are present.

What IRC 2024 Actually Requires

IRC 2024 Section P2903.9.1 states that an individual shut-off valve must be provided on the water supply to each plumbing fixture. The valve must be accessible, meaning a person can reach and operate it without removing or demolishing any part of the building structure. A valve behind a removable access panel satisfies this requirement; a valve soldered inside a wall cavity without access does not.

The requirement applies to both hot and cold supply connections at each fixture. A bathroom lavatory with both hot and cold supply lines requires two shut-off valves — one on the hot line and one on the cold — installed in the exposed supply stub-out between the wall and the faucet supply lines. Toilets have only a cold water supply and require a single shut-off valve. Kitchen sinks typically have both hot and cold valves under the sink. Dishwashers share the hot water supply and must have their own dedicated shut-off, typically an angle stop under the sink that serves only the dishwasher supply line.

IRC 2024 does not mandate a specific valve type for individual fixture shut-offs, but it does require that the valve be accessible and operable. Ball valves are the preferred modern choice because they provide full-bore flow in the open position and positive shut-off with a quarter turn. Compression valves (the older multi-turn type with a rubber seat) are still compliant but are more prone to seat wear and leakage over time. Angle stops — which turn the supply from horizontal (from the wall) to vertical (up to the faucet) — are the most space-efficient configuration under sinks and behind toilets and are almost universally used in modern construction.

The main building shut-off is not addressed by Section P2903.9.1 but is required under Section P2903.9, which mandates a valve on the building supply at or near the point of entry into the building. This main shut-off allows the entire building to be isolated for service. Individual fixture valves allow a single fixture to be serviced without shutting down the entire building supply.

Why This Rule Exists

The requirement for individual fixture shut-off valves serves two practical purposes. First, it allows a leaking or failed fixture component to be isolated and repaired without interrupting water service to the entire building. Without individual shut-offs, repairing a dripping faucet requires shutting off the main, draining the supply lines, and restoring service after the repair — an interruption that affects every fixture in the building. In multi-unit buildings, the lack of individual shut-offs can be especially disruptive. Second, individual shut-offs limit the damage from a supply line failure. A washing machine hose that fails at 2 a.m. can flood a home; if there is a shut-off valve at the washing machine connection that is identified and accessible, a homeowner or emergency plumber can stop the flow in seconds rather than hunting for the main.

The accessibility requirement exists because a shut-off valve that cannot be reached in an emergency is effectively no valve at all. During a plumbing emergency, seconds matter. A valve buried in drywall serves the inspector’s rough-in checklist but does nothing to stop a flood. The IRC’s insistence on accessible valves is a direct response to real-world incidents where hidden valves made emergency isolation impossible.

What the Inspector Checks at Rough and Final

At rough-in inspection, the inspector will confirm that stub-outs are positioned to allow accessible valve installation at each fixture location. The rough-in locations for supply stubs — height from floor, centerline spacing for lavatories and sinks — are checked against the fixture schedule or standard rough-in dimensions. Valves themselves are typically not installed at rough-in because they would be exposed to construction traffic and debris; they are installed at the trim-out stage just before the fixture is set.

At final inspection, the inspector will check every fixture for a shut-off valve on each supply line. The inspector will look under sinks, behind toilets, and at washing machine supply connections. They will confirm that the valve is accessible — that it can be reached and turned without removing any cabinetry, panels, or structure. The inspector will operate the valve by turning it closed and then open again to confirm it is functional. A valve that is corroded in place, was overtightened during installation and cannot turn, or is blocked by cabinetry fails the accessibility requirement.

The inspector will also check that dishwasher shut-offs, which are sometimes overlooked by contractors who think of the dishwasher as an appliance rather than a fixture, are present and accessible. The dishwasher shut-off is typically located under the kitchen sink, accessible through the sink cabinet door.

What Contractors Need to Know

The choice between a ball valve and a compression angle stop is not merely aesthetic. Ball valves provide full-bore flow with minimal pressure drop and will last the life of the fixture without needing seat replacement. Compression valves have a replaceable rubber seat that wears over time (typically 10–20 years), and a worn seat causes the valve to drip past the seat even in the closed position. Specifying ball valve angle stops at all fixture locations is a small upfront cost differential that eliminates the most common service call in residential plumbing.

Valve labeling and identification are not explicitly required by IRC 2024 Section P2903.9.1 for individual fixture valves in single-family homes, but they are required in commercial occupancies and are good practice in any building with multiple similar fixtures. In a home with three bathrooms, labeling the shut-off for each lavatory (“Master Bath Hot,” “Hall Bath Cold”) at the valve or on a nearby label greatly reduces service time when a fixture needs isolation. Some inspectors in jurisdictions with local amendments may require labeling even on residential fixture valves; check local code.

In-wall shut-off valves are used in some applications where under-sink or behind-toilet space is tight, particularly in remodels. If an in-wall valve is used, the access panel must be present and permanently accessible — not concealed behind tile, a mirror, or cabinetry without a removable door. The access panel must be documented in the permit and inspected.

What Homeowners Get Wrong

Many homeowners do not know where their individual fixture shut-offs are located until they need them in an emergency. The best time to learn is before an emergency — do a walkthrough of the entire house, locate every fixture shut-off, and confirm each one can be turned off easily. Shut-off valves that have sat fully open for many years can seize in the open position due to mineral buildup. Exercising the valves annually (turning them closed and then fully open again) prevents this. A valve that cannot be closed is not a functioning safety device.

Another common error is assuming that the main shut-off is the only valve needed. When a lavatory supply line fails under a sink, the time it takes to reach the main shut-off — often in the garage or outside at the meter — and turn it off can allow significant water damage. The individual fixture valve, if it is accessible and operable, allows instant isolation at the point of failure. Training every adult in the household on the location of both the main and individual fixture shut-offs is a basic loss-prevention measure.

State and Local Amendments

Most jurisdictions adopt IRC 2024 Section P2903.9.1 without amendment. A few states and municipalities have added requirements for valve identification labeling or for specific valve types at particular fixture locations. New York City’s plumbing code has detailed requirements for valve accessibility dimensions and identification in multifamily buildings that exceed the IRC baseline. California’s plumbing code aligns with the IRC on individual fixture shut-offs but has additional requirements for the main building shut-off location and visibility, including requirements that the main shut-off be operable from outside the building in some occupancy classifications.

Some local water utilities require that the main shut-off valve on the customer’s side of the meter be a ball valve (not a gate valve), because ball valves provide more reliable positive shut-off in emergencies. While this is a utility service requirement rather than a code amendment, it effectively governs what a contractor must install at the building supply entry, and some inspectors will flag a gate valve at the meter as non-compliant with local utility requirements even if it technically meets the IRC.

When to Hire a Professional

Installing individual fixture shut-off valves during new construction is standard plumber’s work included in any rough-in and trim-out scope. In existing homes, adding or replacing shut-off valves under a sink or behind a toilet is one of the more accessible plumbing tasks: the main must be shut off, the supply pipe cut and fitted with a new valve, and the connection restored before turning the water back on. On copper supply lines, this involves soldering; on PEX, it requires the appropriate fitting tool. If you are not comfortable with soldering or PEX crimp connections, hire a licensed plumber. The risk of an improperly made connection on a fixture shut-off is the very water damage that the shut-off is meant to prevent. A licensed plumber can replace a fixture shut-off valve in under an hour at a cost that is trivial compared to water damage remediation.

Common Violations Found at Inspection

• No shut-off valve on toilet supply; this is among the most common residential plumbing violations at final inspection, particularly when toilets are connected with simple supply tubes and the angle stop is omitted.
• Dishwasher supply connected without a dedicated shut-off valve; the dishwasher is treated as an appliance and its supply connection is overlooked during trim-out.
• Shut-off valve installed inside a wall without an access panel, making it inaccessible without demolition and failing the accessibility requirement.
• Valve installed but seized in the open position due to over-tightening during installation; inspector cannot close it during functional test.
• No separate hot and cold shut-offs at a lavatory; a single valve on only the hot or cold line does not satisfy the requirement for isolation of both supplies.
• Compression valve installed with the stem packing nut tightened so aggressively that the valve cannot be turned without tools, violating accessibility in practice even if the location is accessible.
• Washing machine supply connections using hose bibs without individual shut-off valves separate from the general hose supply; washing machine connections require dedicated, labeled shut-offs per many local amendments.
• Ball valve installed in a fully recessed configuration where the handle cannot be turned more than 45 degrees due to the surrounding structure, preventing full operation of the valve.