A toilet that keeps running can quietly waste hundreds of gallons a day. The cause is usually a cheap, worn part in the tank. Here is what's behind it and how it's fixed.
Written bySteven Lockhart·Reviewed byMiguel Lopez, Owner & Licensed Plumber (CSLB #974600)·Last reviewedJune 2026 · 4 min read
Quick Answer
A running toilet fix usually targets one of two tank parts: the flapper (the rubber seal at the bottom that lets water into the bowl) or the fill valve. A worn flapper lets water leak from tank to bowl, so the fill valve keeps topping it off — that’s the running you hear. Replacing the flapper or fill valve solves most cases. A running toilet can waste a lot of water, so it is worth fixing promptly. This is part of our complete guide to toilet repair in West Los Angeles.
A toilet keeps running when water continuously moves from the tank into the bowl or overflows internally, so the fill valve never shuts off. The usual causes: a worn or warped flapper that no longer seals, a flapper chain that is too tight, a fill valve set too high (sending water down the overflow tube), or a failing fill valve. Each is an inexpensive part. The EPA notes a running toilet is among the most common household water wasters. This guide is part of our complete resource on toilet repair in West Los Angeles.
A running toilet is a toilet whose fill valve keeps cycling because water continuously escapes the tank — usually past a worn flapper or down an overset overflow tube — wasting water until the part is fixed.
A toilet flapper leak is the most common reason a toilet won’t stop running. The table maps the symptom to the likely part and fix.
| Symptom | Likely cause | Fix |
|---|---|---|
| Intermittent refilling | Worn flapper leaking | Replace flapper |
| Constant running | Fill valve set high/failing | Adjust or replace valve |
| Water in overflow tube | Float set too high | Lower the float |
| Phantom flushes | Slow flapper leak | Replace flapper |
Leaking toilet repair in Los Angeles covers more than the tank: a toilet can also leak at the base (a failed wax ring), at the tank-to-bowl connection, or at the supply line. A leak at the base — water around the floor or a rocking toilet — needs prompt attention because it can damage the subfloor. We diagnose where the leak is, fix the responsible part (flapper, fill valve, wax ring, supply line, or bolts), and tell you honestly when an old, inefficient, or cracked toilet is better replaced than repeatedly repaired.
A homeowner hears their toilet cycle on by itself every few minutes and sees the water bill creeping up.
New Pro finds a worn flapper letting water seep into the bowl and replaces it (and checks the fill valve).
The phantom flushing stops, the toilet holds its tank water, and the wasted gallons — and the bill — come back down.
The Bottom Line
A running toilet is almost always a cheap worn part — a flapper or fill valve — but it wastes real water until fixed. We diagnose the cause, replace what’s worn, and flag when an old toilet is worth replacing instead. Call any time. More on our toilet repair page.
Usually a worn flapper that no longer seals (so water seeps into the bowl and the tank refills), a fill valve set too high or failing, or a float that sends water down the overflow tube. Each is an inexpensive part to replace.
Potentially hundreds of gallons a day in a bad case — the EPA lists running toilets among the biggest household water wasters. That is why it is worth fixing promptly, both to save water and to lower your bill.
Often yes — replacing a flapper or adjusting the float is a common DIY fix. If it keeps running after that, the fill valve may need replacing, or there may be a leak elsewhere. We can handle it if you’d rather not, and check for other leaks.
It is the rubber seal at the bottom of the tank that lifts to flush and then drops to hold water. When it wears or warps, it no longer seals, letting water leak into the bowl — the most common cause of a running toilet.
Often a failed wax ring where the toilet meets the floor. Water around the base or a rocking toilet needs prompt attention, since it can damage the subfloor. We reset the toilet with a new seal and check the flange.
For a running toilet, repair (a cheap part) almost always makes sense. Replacement is worth considering for an old, very inefficient, or cracked toilet, or one needing repeated repairs. We’ll give you an honest call.
Written by the New Pro Plumbing content team and reviewed for technical accuracy by Miguel Lopez, owner and California-licensed plumber (CSLB #974600). Pipe lifespans are presented as typical ranges, not guarantees, and any pricing is confirmed in writing before work begins.
What's new: June 2026 — first publication.
We fix running and leaking toilets fast — flat-rate, and we'll tell you if a part or a new toilet makes more sense. Call any time.
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