Three parts that make a toilet run
Inside the tank there are three parts that cause most running toilets: the flapper, the flush valve seat and the fill valve. The flapper is the rubber seal at the bottom. The flush valve is the drain assembly it seals against. The fill valve is the tall unit on the left that refills the tank.
A flapper that no longer seals lets water trickle into the bowl. A flush valve with a pitted or cracked seat does the same, and a new flapper will not cure it. A fill valve that will not shut off sends water over the overflow tube.
If you cannot tell which, the tests below sort it out in a few minutes. For a toilet that still misbehaves after that, our toilet repair service covers the fix.
Symptom, likely part and first move
| What you notice | Likely part | First move |
|---|---|---|
| Toilet refills every few minutes with no one using it. | Flapper or flush valve seat leaking. | Dye test in the tank, then inspect the flapper and seat. |
| Hissing that never stops, water level rises to the overflow tube. | Fill valve not shutting off. | Adjust the float, clean the valve, or replace it. |
| Handle must be held down to flush. | Chain too long or short, or a worn lift arm. | Adjust the chain slack to about half an inch. |
| Water trickles down the side of the bowl. | Flush valve seat or flapper edge. | Wipe the seat, feel for a nick, and replace as needed. |
| Water around the base of the toilet. | Wax ring, supply connection or tank bolt. | Dry everything and watch where the first drop appears. |
| Weak flush, partial rinse. | Clogged rim jets or low tank water level. | Check the water line and clean the rim holes. |
Hold off on buying parts until you know which fits. Toilets come in several flapper sizes, and a mismatched flapper will leak as badly as an old one.
Safe DIY: from shutoff to test flush
Take your time and keep a towel nearby. If any step feels wrong, stop and call.
Close the supply valve
Turn the oval handle behind the toilet clockwise until it stops. Flush once to empty the tank and hold the handle down to drain the last of it.
Sponge out the rest
Use a sponge or old towel to remove the water left in the bottom. A dry tank lets you see the seat and the seal.
Inspect and test
Run a finger around the flush valve seat. It should feel smooth. Any ridge, crack or crust means the seat is the issue. Press the flapper down by hand to check it seals.
Replace the part, refill and test
Swap the flapper or fill valve, open the supply and let the tank fill. Add food coloring to the tank and wait 15 minutes without flushing. Color in the bowl means a leak remains.
Do not overtighten plastic nuts. Hand tight plus a quarter turn is enough, and cracking a tank is a bigger problem than the one you started with.
Wet floor around the toilet?
Shut off the supply valve, sop up the water and keep outlets and cords dry. Water moving across a floor can run under baseboards and flooring, so do not leave it. If the leak is at the base of the bowl, plan to have the toilet pulled and the wax ring replaced.
When the flush valve itself is the problem
Flush valves wear in a few ways. The plastic seat can pit, the overflow tube can crack, and the large rubber gasket that seals the flush valve to the tank can age and weep at the bolt area. A pitted seat can sometimes be smoothed with fine abrasive, but a replacement flush valve is a longer-lasting fix.
Replacing a flush valve means removing the tank bolts and, on many models, lifting the tank off the bowl. That is a two-hand, careful job, and porcelain does not forgive a drop. If the tank is old, tank bolts are often corroded, and a stubborn nut can turn a ten-minute fix into an afternoon.
That is a good point to call. We replace the valve, the gasket and the bolts together so the whole joint is fresh.
Toilet still running after you tried?
A quick call may save a second trip to the store. Call us and tell us what you replaced.
What a running toilet costs you
A toilet that refills on its own can lose water all day and all night without a sound. It adds to the water and sewer portion of your bill because the water goes down the drain unused. There is no safe amount of running to ignore, and it rarely fixes itself.
Your water meter can help you confirm it. Turn off every fixture, check that the meter is still, then look again after an hour. If the dial or low-flow indicator moves, something is leaking, and the toilet is the first place to check. Our leak detection team can trace one if the toilet turns out to be innocent.
Greenacres water service and why it matters here
Greenacres is served through Palm Beach County Water Utilities, so your water bill and any service notices come from PBCWUD. If you see your toilet running, the waste appears on that bill, and the utility is the place to ask about billing questions.
Boil water notices do happen after main breaks. In March 2024, a contractor struck a PBCWUD water main on the south side of Lake Worth Road near Charleston Street, west of Jog Road, and boil notices went to affected households. The practical point is simple: follow the utility's notice, and if you were home when pressure dropped, flush toilets and run taps as the notice directs before assuming a fixture has failed.
Low pressure after such an event can make a fill valve refill slowly or hiss as pressure returns. Give it a little time before you take the tank apart.
Neighbors in Palm Springs and Lantana
Toilet tanks in Palm Springs and Lantana homes have the same three parts, and the same dye test works there. Each town runs its own water system, so check with your own utility for questions about notices or billing.
Fixture parts and the code
Toilets are fixtures covered by the Florida Building Code, Plumbing, which Florida builds on the International Plumbing Code (IPC), which rests on the IPC. A flush valve swap is repair of an existing fixture and does not change the plumbing.
Moving or adding a toilet is a different matter and may need a permit. Ask the building department.
Running toilet questions
Add food coloring to the tank and wait without flushing. Color in the bowl means water is slipping past the seal. If a new flapper does not fix it, the seat on the flush valve is probably damaged.
Usually, yes. Shut off the supply, drain the tank, disconnect the supply line, swap the valve and reconnect. Do not overtighten plastic parts, and check the supply connection for drips before you walk away.
That is often called a phantom flush. A slow leak lowers the tank level until the fill valve opens briefly. The cause is usually a flapper or seat.
Yes. The water goes down the drain unused, and it adds to the water and sewer charges. Fixing it sooner means less water wasted.
Follow the instructions in the notice from the utility. A boil notice is about drinking and cooking water, and toilets work as usual. Slow refills after pressure returns are normal for a short time.
Call if the tank bolts are corroded, the tank must be lifted, water is at the base of the bowl, or you have tried two parts and the toilet still runs.