Toilet Repair Guide: Troubleshooting Common Issues at Home

A toilet that won’t flush, leaks, or runs all night is more than annoying. It can spike your water bill, damage your floors, and—if you’re unlucky—turn a minor inconvenience into a full-blown emergency plumbing issue.

At Alexanders Plumbing, we’ve seen it all. From century-old pipes in historic homes to the latest models with water-saving tech, our licensed plumbers know what works—and what can wait. Here’s a straightforward guide to help you handle common toilet troubles at home.

Common Toilet Issues 🚽

Toilets are workhorses, but even the best ones hit a snag now and then. Here are problems we see most often:

• Toilet won’t stop running
• Weak, incomplete flushes
• Water pooling around the base
• Toilet tank won’t fill up
• Phantom flushes (toilet flushes on its own)
• Clogs that won’t budge
• Unusual noises after flushing

Each problem can have a simple fix—or might be a sign something bigger lurks below. Let’s break it down.

Quick Safety Checklist

Before you reach for a wrench or open the tank, keep these safety tips in mind:

• Turn off the water supply behind the toilet (look for the small valve near the floor).
• Never use boiling water to clear a clog—hot water can crack porcelain.
• Wear gloves to protect against bacteria and cleaning chemicals.
• Don’t force parts if they’re stuck—older toilets and pipes can be brittle.
• Check your warranty—some DIY fixes are safe, but breaking parts may void coverage.

If you’re unsure, or if you smell gas or see water gushing out, stop and call a professional right away.

DIY Fixes: Flapper, Fill Valve, and Leak Repairs

Some problems are simple enough for a confident DIYer. Here’s how to tackle the most common culprits.

The Flapper: The Usual Suspect

If your toilet runs nonstop, the flapper (the rubber seal at the bottom of the tank) may not be sealing properly.

Steps to Replace a Flapper:

1. Turn off the water supply.
2. Flush to empty the tank.
3. Unhook the old flapper from the overflow tube.
4. Attach the new flapper—make sure it sits flat.
5. Reconnect the chain (leave a little slack).
6. Turn the water back on and test.

Tip: For older homes, parts may be worn or hard to match. Take the old flapper to a hardware store for a perfect fit.

Fill Valve: When the Tank Won’t Fill

A faulty fill valve leaves the tank empty or filling too slowly.

How to Replace a Fill Valve:

1. Shut off the water and drain the tank.
2. Unscrew the supply line from the bottom of the tank.
3. Remove the old fill valve (usually a large plastic nut).
4. Insert the new valve, adjust to height, and tighten.
5. Reattach the supply line, turn on the water, and check for leaks.

Note: Modern fill valves are adjustable, but follow the instructions. Over-tightening can crack the tank.

Leaks: Spotting and Stopping

Water around the base? A faulty wax ring or loose bolts may be to blame. Here’s how to check:

• Dry the area and flush—does fresh water appear?
• Gently tighten the floor bolts (don’t overdo it).
• If leaking continues, the wax ring may need replacing. This is a bigger job—if you’re not comfortable lifting the toilet, call a plumber.

For tank leaks: Look for hairline cracks or water seeping from bolt holes. Small leaks can turn into big problems fast.

When to Call a Plumber

Some issues need a professional touch—quickly.

• Persistent leaks despite trying new parts
• Water pooling from under the toilet (potential sewer gas hazard)
• Clogs that won’t clear with a plunger or auger
• Cracked porcelain
• Gurgling sounds in other drains (sign of sewer line trouble)
• Low water pressure issues near you affecting multiple fixtures

If you live in an older home, be aware: pipes and connections may not match modern parts. For any uncertainty, Alexanders Plumbing is just a call away.

Preventative Tips for Toilet Health

An ounce of prevention saves a pound of headaches. Here’s how to keep your toilet running smoothly:

• Only flush toilet paper—no wipes, cotton balls, or hygiene products.
• Regularly check for leaks inside the tank (add a few drops of food coloring; if it seeps into the bowl, you have a leak).
• Avoid chemical drain cleaners—they can corrode pipes and seals.
• Tighten bolts and parts gently—over-tightening can crack porcelain or distort seals.
• Schedule annual inspections—especially important in older homes with original plumbing.

The Uniform Plumbing Code (UPC) recommends periodic checks of all fixtures and connections for leaks or wear—good advice for any homeowner.

Costs & Time Factors

How long will it take? How much will it cost? Here’s what to expect:

• Simple flapper or fill valve replacement: 15–30 minutes, minimal cost for parts.
• Wax ring replacement: 1–2 hours (may require professional help, especially in older homes).
• Persistent clogs or leaks: Diagnostic time varies, plus parts/labor if needed.
• Extensive repairs in older homes: May require specialty parts or repiping, which takes more time and skill.

Most basic repairs are wallet-friendly. But if your toilet is over 20 years old or you’re seeing frequent problems, it may be more cost-effective to upgrade.

When It’s an Emergency

Some toilet problems can’t wait:

• Overflowing toilet that won’t stop (turn off water supply right away)
• Sewage backing up into bathtub or sink (sign of main line blockage)
• Water spraying from supply line or tank cracks
• Foul sewage odors in the bathroom

These situations can cause water damage, health hazards, and require emergency plumbing help.

Frequently Asked Questions

How do I know if my toilet is leaking?
Look for unexplained water on the floor, listen for running water when no one’s using it, or use the food coloring test in the tank.

Is it safe to use a plunger on a modern toilet?
Yes, but use a flange-style plunger for a good seal. Don’t use metal tools that can scratch porcelain.

Can I replace a toilet myself?
It’s possible, but toilets are heavy and awkward. If you’re unsure, backflow prevention and proper sealing are best left to a pro.

Why does my toilet make gurgling sounds?
This may signal a blockage in your vent pipe or sewer line. Contact a plumber for a thorough sewer line inspection.

Local and Seasonal Considerations

Older homes in your area may have cast iron or clay pipes, which are more prone to leaks and blockages. In colder months, pipes can contract and cause seals to fail. If you notice recurring issues during certain seasons, it may be time for a preventative maintenance check.

If you’re dealing with water pressure issues near you, or your home has unique plumbing quirks, Alexanders Plumbing is always ready to help.

If your DIY fixes don’t solve the problem—or if water is rising fast—don’t wait. Call Alexanders Plumbing now — or reach us anytime at  877-837-7096 .