As a home improvement expert who has renovated dozens of bathrooms, I know how annoying and wasteful a toilet that keeps running after flushing can be. But there’s no need to keep dealing with the problem or call a plumber right away. With the right knowledge and a few replacement parts, you can often fix a constantly running toilet yourself in less than an hour.
In this comprehensive DIY guide, I’ll walk you through the entire process step-by-step. I’ll explain:
- The most common reasons a toilet runs too long
- How to accurately diagnose the issue
- Fixing or replacing faulty parts
- Adjusting components correctly
- Testing to ensure it operates properly
Let’s start by reviewing the inner workings of your toilet tank so you understand exactly what makes it tick. Once you know how the various components function together, it will be much easier to troubleshoot and repair running issues.
Anatomy of a Toilet Tank
Your toilet tank contains several critical components that allow it to function:
- Flapper valve – The rubber seal that lifts up to release water into the bowl when you flush. It seals again when the tank refills.
- Fill valve – Lets water flow into the tank to refill it after flushing. Shuts off automatically when full.
- Float ball – Connected to the fill valve and causes it to shut off once water reaches a preset level.
- Overflow tube – Allows water to drain out if the tank overfills. Keeps it from spilling onto the floor.
- Flush valve – Lifts up when you flush the handle, allowing the tank to empty into the bowl.
- Trip lever – The flushing handle that you press, which lifts the flapper and flush valve.
Now let’s explore why each of these toilet components could cause continuous running issues.
Common Causes of a Toilet That Keeps Running
Based on fixing hundreds of toilets in my career, these are the most common offenders:
1. Worn Out Flapper Valve
This is the most likely culprit if your toilet runs after flushing. The flapper is made of rubber, so it wears out over time and deforms. When this happens, it won’t seal tightly against the flush valve anymore, allowing water to continuously trickle from the tank into the bowl.
According to a report by the Water Research Foundation, up to 18 percent of toilets have leaky flappers resulting in water loss. Replacing an old and leaky flapper with a new one will instantly stop the running problem in most cases.
2. Fill Valve Not Shutting Off
The fill valve is supposed to add just the right amount of water into the tank after you flush and then shut off automatically when full. However, if the valve is old, dirty, or worn out, it can get stuck open.
This results in water endlessly flowing into the tank, down the overflow tube, and into the bowl, creating the running sound. Swapping in a new fill valve solves this issue.
3. Fill Valve Seal Leaking
Even if the fill valve is shutting off properly, it could still leak water due to a damaged seal. Check the water supply line where it connects to the bottom of the valve. If you see water droplets there, the seal is likely cracked or worn and needs replacement.
4. Problems with the Float Ball
The float ball should rise along with the water level in the tank. This triggers the fill valve to close when full. If the float gets stuck, water will overfill the tank and run down the overflow. Readjusting the float ball’s angle and height prevents this.
5. Overflow Tube Issues
The overflow tube drains away excess water. But if it gets clogged, water can’t exit fast enough during refilling and will spill over into the bowl. The tube may also become misaligned or damaged. Adjusting or replacing it solves the problem.
6. Chain Too Loose
The chain connecting the flapper valve should have just a tiny bit of slack. Too much slack can prevent the flapper from sealing fully after flushing, allowing leakage. Tightening the chain is an easy fix.
7. Warped or Unsealed Flush Valve
The flush valve at the bottom of the tank can sometimes become warped or unsealed from mineral deposits. This allows water to drip from the tank directly into the toilet bowl, without waiting for a flush. Reseating or replacing the valve gasket prevents leakage.
8. Poorly Seated Tank Gaskets
If the gaskets between the tank and bowl are damaged or improperly set, water can leak through these spots and go straight down the drain. Readjusting tank mounting bolts and checking gasket positions will fix leaks here.
Now that you know what makes a toilet run, it’s time to diagnose your specific problem.
Step-by-Step Diagnosis and Repair Instructions
Follow these steps to accurately pinpoint the cause of your running toilet and fix it. I’ll go through each toilet tank component one-by-one:
1. Turn Off Water Supply
- Locate the water supply valve behind or near the toilet and turn it clockwise to shut off water to the tank.
2. Flush Toilet and Empty Tank
- Flush the toilet to drain all water from the tank into the bowl.
- Use a small cup or sponge to remove any remaining water in the bottom of the tank.
3. Check the Flapper Valve
- Lift the flapper up out of the drain at the bottom of the tank.
- Inspect its shape, thickness, and flexibility. It should be made of soft, pliable rubber.
- Look for any cracks, warping, mineral deposits, or deterioration.
- If it doesn’t look smooth, soft, and well-sealed, replace it with a new flapper.
4. Ensure Proper Flapper Chain Length
- Make sure the chain has only 1⁄2 inch of slack. More can prevent a tight seal.
- Loosen chain from flapper if needed and remove links or adjust position.
5. Clean and Inspect Flush Valve Seal
- Check the flush valve seal inside tank for dirt, buildup, or damage.
- Use a sponge and white vinegar to clean seal of any deposits.
- Make sure rubber seal is properly seated and sealing against flapper.
6. Assess Fill Valve
- Listen closely to see if you hear water running into tank from fill valve after flush.
- If it sounds like valve isn’t shutting off fully, replace the fill valve.
7. Check Fill Valve Seals
- Inspect seal between fill valve and tank for cracks or leaking.
- Also check seal where water supply line connects to bottom of fill valve.
- If any seals are damaged, replace fill valve.
8. Examine Float Ball
- Flush toilet and observe if float ball rises and triggers fill valve to close.
- Ensure float ball is free of obstructions and operating smoothly.
- Bend float rod slightly if needed to adjust float height to stop at proper level.
9. Inspect Overflow Tube
- Check that tube is securely fitted upside down into overflow drain hole.
- Clear any obstructions like algae or debris from inside tube.
- Straighten or replace tube if necessary.
10. Test Toilet Tank Components
- Turn water supply back on and let tank refill.
- Flush toilet several times and observe operation of all components.
- Make any necessary adjustments.
- Check for leaks and signs of running water.
Be methodical in your diagnosis. Go through each step carefully while thoroughly inspecting each toilet component. Taking the time to do this will allow you to accurately identify the problem.
In most cases, you’ll discover the running issue is due to a single faulty part like an old flapper, leaky fill valve seal, or damaged overflow tube. Replacing just that one part is all that’s needed to fix the problem.
Replacing Toilet Tank Components
Once you’ve identified the specific component that’s malfunctioning, replacing it is a straightforward process:
Purchase the Replacement Part
- For flappers, bring the old one with you to find an exact match. There are many shapes, sizes and styles.
- Choose an appropriate fill valve, float ball, or overflow tube depending on your toilet model.
- Use a kit to replace multiple gaskets and bolts at once if needed.
Shut Off Water Supply and Flush Out Tank
- Turn off supply valve and flush out all water again before replacing any part.
Remove Old Part and Clean Surfaces
- Disconnect any chains or tubes attached to the part.
- Unscrew any nuts or bolts securing it.
- Use a scouring pad and white vinegar to scrub away residue on seating surfaces.
Install New Replacement Part
- Read instructions to ensure proper orientation and positioning.
- Attach any necessary chains, bolts, or connections.
- Confirm part is level, aligned, and moves smoothly.
- Overtightening can damage new parts, so take care.
Turn Water On and Test
- Turn supply back on and let tank fully refill.
- Flush the toilet several times and observe operation.
- Adjust or tighten new part if needed.
Confirm Running Has Stopped
- After replacement, you should no longer hear water trickling into the bowl.
- Verify fix by letting toilet sit for a few hours, then check again for running.
Follow the manufacturer’s directions closely when installing replacement parts. Adjust positions, water levels, and slack as needed until components function optimally together. Get it right and the fix should last for years.
Symptoms That Indicate Professional Help Is Needed
While the majority of constant toilet running issues can be fixed DIY, there are a few symptoms that signal it’s time to call a professional:
- Water in tank rises extremely slowly – Points to low water pressure.
- Running starts again immediately after adjustments – Valves likely need full replacement.
- Running is random, not every flush – Indicates an obstruction somewhere in the tank.
- Replacing parts didn’t fix running – A pro can identify the tricky cause.
- Running causes overflowing or leaks – Critical plumbing issue needs addressing.
A competent plumber has specialized equipment, like pressure gauges and camera snakes, to fully diagnose toilet problems and make comprehensive repairs. They can also check pipes and valves hidden below the tank.
Prevent Future Toilet Running Issues
Once you’ve stopped that dreadful post-flush trickling sound, here are some tips to help prevent running problems going forward:
- Check flapper seal yearly – Replace flapper if stiff, warped, or doesn‘t lay flat and seal fully.
- Avoid aggressive in-tank cleaners – Over time they can degrade flapper valve and other components.
- Listen for running water – Periodically check that water in tank fully stops flowing after refilling.
- Replace tank parts proactively – Flappers, fill valves, and float balls wear out. Swap every 5-7 years.
- Avoid over-tightening bolts – This can warp parts. Hand tighten plus 1⁄4 turn with pliers is sufficient.
- Don’t use drop-in cleaners – They can dissolve flapper valves and inner gaskets over time.
With proper toilet maintenance and replacement of worn parts as needed, you can avoid annoying and wasteful running toilet issues. Share your newfound DIY knowledge with family and friends to save on plumber bills.
I hope you found this guide helpful. Let me know if you have any other home improvement challenges I can help you tackle. Fixing things ourselves not only saves money, but gives a great sense of accomplishment and self-reliance.
