Toilet Keeps Running
Your toilet runs constantly or intermittently after flushing, wasting water.
Toilet Keeps Running: A running toilet is usually caused by a worn flapper valve, a faulty fill valve, or an improperly adjusted float. A worn flapper is the most common cause and costs $5–$15 to replace yourself. If the toilet runs constantly, it can waste 200+ gallons per day. Professional repair costs $100–$250 if DIY isn't an option.
What Causes This?
Worn Flapper Valve
The rubber flapper at the bottom of the tank seals water between flushes. Over time it warps, cracks, or accumulates mineral deposits, allowing water to seep into the bowl constantly.
Faulty Fill Valve
The fill valve controls water refilling the tank after a flush. A worn valve can fail to shut off completely, causing continuous running.
Float Adjusted Too High
If the float is set too high, water rises above the overflow tube and drains continuously. Adjusting the float level down fixes this.
Overflow Tube Issue
A cracked overflow tube or one that's too short allows water to constantly drain from the tank into the bowl.
Flush Valve Seat Damage
The surface where the flapper seats can become rough or corroded, preventing a proper seal even with a new flapper.
Can It Wait?
A running toilet isn't an emergency, but it wastes significant water — up to 200 gallons per day. Fix it promptly to avoid a high water bill. If water is overflowing onto the floor, that's urgent.
What Does It Cost?
| Item | Cost Range |
|---|---|
| Flapper Replacement | $5–$15 |
| Fill Valve Replacement | $15–$30 |
| Professional Repair | $100–$250 |
| Toilet Replacement (if warranted) | $250–$600 |
Repair vs. Replace
Repair
Repair if: the toilet is in good condition and the issue is a flapper, fill valve, or float adjustment. These are inexpensive fixes.
Replace
Replace if: the toilet has cracks, wobbles on the base, or needs frequent repairs. Modern low-flow toilets use 1.28 GPF vs. older models using 3.5–5 GPF, saving water and money.
Rule of thumb: Toilet internals (flapper, fill valve) are cheap and easy to replace. But if the toilet itself is old, cracked, or uses excessive water, a $250–$600 replacement saves water long-term.
When to Call a Contractor
- ✓You've replaced the flapper and the toilet still runs
- ✓Water is leaking from the base of the toilet
- ✓The toilet rocks or wobbles on the floor
- ✓You hear constant running and can't identify the source
- ✓Multiple toilets are running (may indicate a pressure issue)
Related Problems
Toilet Keeps Running — FAQ
How do I fix a running toilet?
Start by jiggling the flush handle — if it stops, the flapper chain is too long or tangled. Next, lift the tank lid and check the flapper: if it's warped or doesn't seal, replace it ($5–$15 at any hardware store). If the water level is above the overflow tube, adjust the float down.
How much water does a running toilet waste?
A continuously running toilet can waste 200+ gallons per day — that's 6,000 gallons per month. At typical water rates, that's $50–$100+ per month in wasted water. Even an intermittent run can waste 20–50 gallons per day.
Should I replace my toilet or just repair it?
Repair if: the toilet is structurally sound and just needs a flapper or fill valve ($5–$30 DIY). Replace if: the toilet is cracked, uses more than 1.6 GPF (check the stamp inside the tank), or needs repeated repairs. Modern toilets cost $250–$600 installed.