Supply Line Leak Repair
Supply lines are the flexible hoses connecting your shutoff valves to faucets, toilets, and appliances. They fail from age, corrosion at the fittings, kinks, or burst braiding — often leaking inside cabinets where damage spreads unseen. A plumber replaces the failed line and inspects the shutoff valve. FlowFast connects you with an independent local plumber for fast supply line repair.
- Connected with an independent local pro — never a call center queue.
- Part of our Leak Detection & Repair services — explained up front.
Parent service
Leak Detection & RepairHigh water bill or mystery damp spot? How pros find hidden leaks with acoustic and thermal tools, and how to get connected with an independent local plumber.
View all Leak Repair servicesEvery sink, toilet, dishwasher, and washing machine in your home is fed by short flexible supply lines — usually braided stainless steel or reinforced polymer — running from a shutoff valve to the fixture. They are under full water pressure around the clock, and they are one of the most common sources of indoor flooding when they fail. A pinhole in a braided line can spray a fine mist inside a vanity cabinet for weeks before anyone notices, rotting the cabinet floor and subfloor.
Supply lines typically last about five to ten years depending on water quality and installation. Corrosion at the brass fittings, kinks from being bent too tightly, and deterioration of older rubber-core lines are the usual failure modes. Because the failure is often hidden, the first sign is a swollen cabinet bottom, a musty smell, or a water bill that creeps upward. A plumber shuts off the valve, swaps the failed line for a new braided line of the correct length, and checks the shutoff valve itself — a valve that will not fully close gets replaced at the same time. FlowFast Plumbing is a referral service: we connect you with an independent local plumber who stocks the right lines and fittings to finish the job in one visit.
Warning signs
Signs you need this service
- Water pooling inside a sink cabinet or around a toilet base with no obvious fixture leak above it.
- A swollen, warped, or discolored cabinet floor under a sink — the classic sign of a slow supply-line weep.
- Visible corrosion, green crust, or rust on the fittings where the supply line meets the valve or fixture.
- A hissing or fine spray sound inside a cabinet when the house is quiet, especially after using the fixture.
What to expect
The process, step by step
The pro shuts off the fixture's angle-stop valve and relieves pressure, then dries the area to pinpoint the exact leak point.
The failed supply line is disconnected from both the valve and the fixture, and the shutoff valve is tested — a valve that will not hold gets replaced.
A new braided stainless supply line of the correct length and fitting size is installed, tightened to spec without over-torquing.
Water is restored slowly while the pro watches every connection, then the cabinet is checked for residual moisture and drying advice is given.
Prevention
How to avoid this problem
- Replace braided supply lines every five to eight years, and sooner if you see any corrosion on the fittings.
- Never kink a supply line during installation — sharp bends weaken the braiding and invite pinhole failures.
- Exercise shutoff valves twice a year by turning them off and on, so they actually work when a line fails.
Frequently asked questions
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