By Gold Country Plumbing of El Dorado Hills · Updated July 14, 2026
A toilet keeps running because water is leaking from the tank into the bowl, or the fill valve cannot shut off. In most cases the culprit is a worn flapper, a flapper chain that is too short or too long, or a fill valve that needs adjusting or replacing. These are inexpensive parts, and a running toilet can waste a lot of water over a month, so it is worth fixing quickly.
In Cameron Park and across El Dorado Hills, moderately hard water leaves mineral deposits that harden rubber parts and keep flappers from sealing. That makes a running toilet one of the most common calls we get. Here is how to find the cause in about ten minutes and what you can safely fix yourself.
Start with the dye test
Before touching anything, confirm where the leak is. Remove the tank lid, drop a few drops of food coloring into the tank, and wait fifteen minutes without flushing. If color shows up in the bowl, the flapper is leaking. If the bowl stays clear but you still hear water running or hissing, the problem is the fill valve or the overflow tube.
This single test splits the problem in half and saves you from replacing parts that were fine. It costs nothing and works on every standard toilet. If the tank is not filling at all or the toilet is leaking at the base, that is a different problem, and a different fix.
Worn flapper or a bad chain
The flapper is the rubber seal at the bottom of the tank that lifts when you flush and drops to close the drain. Over time it warps, hardens, or collects mineral film from hard water, and it stops sealing. Water then trickles past it into the bowl, the tank level drops, and the fill valve kicks on to refill it, over and over.
Check the chain too. If it is too short, it holds the flapper slightly open. If it is too long, it can slip under the flapper and block it from closing. Leave about a half inch of slack. A new flapper is a cheap, quick swap, and matching the right size to your toilet model is the only real trick.
Fill valve problems and water level
If the dye test comes back clean, look at the water level. Water should sit about an inch below the top of the overflow tube. If it is higher, water spills into the tube and runs continuously. That means the fill valve is not shutting off, either because the float is set too high or because the valve itself has worn out.
Many fill valves have an adjustment screw or a clip on the float arm. Lower the float and flush. If the hissing continues, the valve seals are likely worn, and replacement is the real fix. Sediment and scale can also keep the valve from closing, which is common in homes on hard water. Replacing the valve usually takes less than an hour.
What a running toilet costs you
A running toilet is not just noise. A steady leak can add up to hundreds of gallons a day depending on how bad it is, and it shows up on your water bill. Even a slow leak adds scale to the bowl and wears parts faster.
Repair costs are modest. Sacramento-area planning benchmarks put toilet repair at roughly $100 to $350, depending on parts and whether the problem is a simple flapper or a worn flush mechanism. That range is a planning figure rather than a quote from us, and the number we give you is flat-rate and confirmed before we start.
When to stop DIY and call a plumber
Simple parts are fair game for a homeowner. Some situations are not.
- You replaced the flapper and fill valve and it still runs: the flush valve seat may be pitted or cracked.
- Water is leaking at the base of the toilet or the supply line: the wax ring or a connection has failed.
- The tank is cracked or the bolts are corroded and spinning.
- The toilet is older, or the parts are no longer available, and replacement makes more sense than another repair.
- You are seeing wet spots on the floor or ceiling below: stop, shut the supply valve, and call.
Repair or replace the toilet?
If the toilet is relatively recent and the part is cheap, repair is the clear choice. If it is a decades-old model with a cracked tank, repeated failures, or an inefficient flush, a new toilet may save water and trouble. We install and repair both, and we will tell you which makes sense.
To get a running toilet fixed, call Gold Country Plumbing at (831) 290-4327. We are licensed (C-36), bonded, and insured, with flat-rate pricing and a 4.9-star record across 214+ reviews.