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How to Troubleshoot and Repair Common Toilet Problems

Bert spent 25 years working as a home-improvement and residential construction contractor in central Florida.

Oftentimes the hardest part of toilet repair is the trip to the hardware store.

Oftentimes the hardest part of toilet repair is the trip to the hardware store.

Fixing Toilet Problems at Home

A few words that nobody ever wants to hear are, "Honey, something is wrong with the toilet." That "something" could end up being anything from a simple fix to a complete rebuild.

But after learning how a toilet operates, troubleshooting becomes easy. Most repairs only take a few minutes to complete. In fact, with the proper tools, a complete tank rebuild often takes an experienced plumber or handyman less than an hour to complete.

This guide will go over how to troubleshoot the following issues:

  1. Toilet Seat Replacement
  2. Toilet Handle Replacement
  3. Flush Valve Problems
  4. Fill Valve and Ballcock Problems
  5. Water Leaks Between the Tank and Bowl
  6. Water Leaks Around the Toilet's Base
  7. Loose Closet Bolt Caps
  8. Clogged Toilet
  9. Slow or Incomplete Flush

How a Toilet Works

All toilets contain a fill valve, handle, and flush mechanism inside the tank. A water supply line feeds water to the fill valve's intake port. A float controls the fill valve's action. When the water level drops below the lower set point, the fill valve turns on. Once the water level reaches the upper set point, the fill valve turns off.

Depressing the toilet's handle activates the flush mechanism, usually either a rubber flapper or power-flush cylinder. With the flush mechanism activated, water rushes from the tank into the bowl. The water should carry any waste in the bowl through the toilet's drain channel and into the building's drain pipe.

A closet flange, the plumbing fitting attached to the end of the home's drain pipe, centers the toilet's discharge port over the drain pipe. A wax ring fills the space between the toilet's discharge port and the closet flange. Two closet bolts, sometimes called bowl-to-floor bolts, hold the bowl in place.

A decorative toilet seat can personalize a bathroom.

A decorative toilet seat can personalize a bathroom.

1. Toilet Seat Replacement

A toilet seat fits either a round or an elongated bowl. Manufacturers also offer upgraded models with features such as a slow-close or no-slam lid, padded seats and decorative designs. All seats share the same replacement instructions.

  1. Remove the old seat: Open the hinge bolt covers. Remove the nut, located under the bowl, holding one of the bolts in place. Repeat this on the other hinge bolt. Remove the old seat.
  2. Prepare the bowl: Clean any buildup that formed on the bowl underneath the old hinge. Fill the hinge-bolt holes in the bowl with silicone or bathroom-caulking.
  3. Position the seat: Set the seat on the bowl and align the holes in the hinges with the bowls'.
  4. Install the bolts: Slide a bolt into each hole. Reach under the bowl and tighten a nut on each bolt. The wet caulking acts like a thread sealant and once dry it keeps the seat from shifting.

2. Toilet Handle Replacement

A lever-style toilet handle comes from the manufacturer with a plastic or metal rod attached to the handle's mounting lug. The mounting lug acts as the handle's pivot point. When the operator pushes down on the handle, the rod lifts the flush mechanism.

  1. Remove the old handle: Lift the tank's lid and remove the flapper chain from the handle's rod, if applicable. Remove the nut securing the handle against the tank. Slide the handle out of its tank opening.
  2. Prepare the new handle: Position the old and new handles next to each other and compare the shapes of the rods. Carefully bend the new handle rod, using the old handle as a guide, until they match.
  3. Install the new handle: Work the rod through its tank opening. Push the handle's square hub into the tank hole. If using a handle with a plastic hub, expect a tight fit. Slide the nut over the rod and hand tighten the nut.
  4. Connect the flapper: Slip the flapper chain into the appropriate hole in the rod, the chain should have a little play in it with the flapper closed.
It is time to replace this defective flapper-style flush valve. Notice the warped rubber flange.

It is time to replace this defective flapper-style flush valve. Notice the warped rubber flange.

3. Flush Valve Problems

Normally when the toilet's flush valve fails, water slowly seeps from the tank into the bowl. Eventually the water level in the tank drops enough to turn on the fill valve, creating a phantom flush.

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Flapper-Type Flush Valve

The flapper connects directly to the tank's overflow tube and covers the tank's discharge port. Some flappers use replaceable chain links between the flapper and the toilet handle. If the chain breaks, either replace the chain or the entire flapper.

Over time, the flapper's rim deteriorates and the edges curl, creating the leak that causes a phantom flush. If the edges of the flapper curl at all, replace the flapper.

  1. Disconnect the handle attachment and the overflow tube's connection.
  2. Lift the old flapper out.
  3. Set the new flapper in place and reattach the handle and tube connection.

Cylinder-Style Flush Valve

This type of flush valve uses a flat round gasket to seal the flush cylinder against the flush valve's base. The rubber seal curls as it ages, which prevents the cylinder from sitting flush against its base.

Because the exact directions differ between manufacturers and styles, those unfamiliar with their exact flush valve model should check the manufacturer's website for a schematic. However, most valves have similar instructions.

  1. Find the shaft located in the center of the cylinder.
  2. Grip the shaft and twist it counterclockwise until it releases.
  3. Remove the cylinder and peel the old seal off.
  4. Apply a new seal, and then reassemble.
Use the threaded rod between the actuator arm and the float to adjust the tank's water level.

Use the threaded rod between the actuator arm and the float to adjust the tank's water level.

4. Fill Valve and Ballcock Problems

A toilet's fill valve, or ballcock, uses a float activated valve. The float rides on the water's surface. When the water level drops below a set point, the float turns on the fill valve. Once the water rises to a second set point, the float turns off the valve.

Improper float travel causes most fill valve issues. In most cases, it makes sense to replace the valve instead of trying to repair it.

Troubleshoot the Fill Valve

  1. Remove the tank's lid and inspect the water level.
  2. If the valve failed to fill the tank with water, tap on the float with a finger to see if water deposits prevent free travel.
  3. If the water turns on, check for water deposits near the top of the fill valve's shaft or actuator.
  4. If the water level has risen over the top of the overflow tube and the fill valve remains in its lowered or on position, lift up on the float.
  5. Check for deposits near the bottom of the shaft or actuator.

Occasionally removing water deposits corrects the issue temporarily. If the float continues to stick, replace the fill valve. Replacement parts exist that fix many leaking fill valves. However, the cost of the parts often rivals the price of a brand new fill valve.

Replace the Fill Valve

  1. Turn off the toilet's angle stop.
  2. Flush the toilet and remove as much water from the tank as possible.
  3. Disconnect the water supply line from the old fill valve.
  4. Remove the nut holding the fill valve in place.
  5. Pull the old fill valve out of the tank.
  6. Clean the inside surface of the tank near the fill valve’s port with a rag.
  7. Install the gasket on the new fill valve’s threaded intake port and the small tube that feeds water to the overflow tube.
  8. Slip the new valve’s intake port through the tank’s port.
  9. Hand tighten the locking nut.
  10. Adjust the float’s positioning so it operates freely inside the tank.
  11. Tighten the nut 1 full turn with a wrench.
  12. Install the water supply line.
  13. Insert the small tube into its overflow tube holder.
  14. Turn on the angle stop and test the valve.

Adjust the Float

  1. Flush the toilet and let the water level settle.
  2. Check the water level against the overflow tube's height. The water should rest about 1/2 inch below the top of the overflow tube.
  3. Adjust the threaded rod between the float and the valve's actuator arm as needed.
Water leaking between the tank and bowl indicates worn gaskets or seals. Because of the age of the other parts inside, this toilet received a complete rebuild kit, which included new gaskets and seals.

Water leaking between the tank and bowl indicates worn gaskets or seals. Because of the age of the other parts inside, this toilet received a complete rebuild kit, which included new gaskets and seals.

5. Water Leaks Between the Tank and Bowl

Occasionally a water leak can be traced to the space between toilet's tank and bowl. In this case suspect either the rubber gaskets on the tank-to-bowl bolts or one of the overflow tube's gaskets. Plumbers often change both sets of gaskets at the same time.

I normally purchase a Fluidmaster complete rebuild kit that matches the flush valve's size and style and then replace everything in the toilet.

  1. Identify the leaking gasket: Turn off the water supply and dry the area completely. Do not use the toilet for 30 minutes and recheck for moisture. If the tank leaked water, suspect the tank-to-bowl bolt gaskets or the overflow tube's internal gasket. If the space remained dry, flush the toilet and check for moisture again. If the tank leaked during the flush, replace the overflow tube's tank-to-bowl seal. This seal hugs the tube's locking nut and only leaks during the flush.
  2. Remove the tank: Disconnect the water supply line from the fill valve. Remove the nuts holding the tank-to-bowl bolts in place. Lift the tank from the bowl and set aside.
  3. Replace the offending gasket: Use a rag to clean the tank's internal surface. Install the appropriate gasket. Some tank-to-bowl bolt kits include the overflow's tank-to-bowl seal.
  4. Install the tank: Set the tank in place. Hand tighten a nut on each tank-to-bowl bolt. Carefully tighten each nut three full turns with a wrench. Connect the supply line and turn on the angle stop. Check for leaks. If the tank-to-bowl gasket leaks, tighten each tank-to-bowl nut one full turn. Use care to avoid over tightening the nut; as this will damage or break the bowl's flange.
A damaged wax ring shows up as seepage around the toilet's base.

A damaged wax ring shows up as seepage around the toilet's base.

6. Water Leaks Around the Toilet's Base

A wax ring seals the closet flange-to-toilet connection. When installed on a properly set toilet, a wax ring often lasts 10 years before it fails due to age. However, a wax ring will lose its integrity quickly when installed on a toilet bowl that shifts every time someone sits on it. If water seeps out from under the toilet after each flush, suspect a damaged wax ring.

  1. Remove the toilet: Turn off the toilet's angle stop and flush the toilet, emptying the tank. Remove the water in the bowl with a plunger. Disconnect the water supply line. If the valve fails, turn off the building’s water supply at either the water meter or the well pump. Remove the caps covering the closet bolts and then remove the nuts. Lift the toilet straight up and set it aside on a piece of cardboard or another type of floor protection material.
  2. Inspect the closet flange and floor: Verify the closet flange remains fully intact. Plumbers often repair a damaged flange with either a metal replacement ring that screws on top of the existing flange or half moon-shaped pieces of metal that slide under the old flange. In some cases, a toilet bowl that rocks was installed on an out-of-level floor tile without shims.
  3. Install a new wax ring and closet bolts: A wax ring kit contains a wax ring and new closet bolt hardware. Some upgraded wax rings utilize a no-seep rubber collar. The collar slips into the closet flange and divert the waste water away from the closet flange. If the top of the closet flange rests above the finished floor's surface, use a standard thickness wax ring. If the closet flange sits below the finished floor's surface, install a thick wax ring or a closet flange spacer. Slide the closet bolts into their respective keyhole-shaped openings on the closet flange. Center the wax ring over the flange's opening and gently press down.
  4. Reset the toilet: Set the toilet in place and gently push down on the bowl until the bowl's bottom edge starts to touch the floor. Position a bubble level across the bowl and adjust the toilet for level. Place composite or plastic shims underneath the bowl, as needed. This helps correct uneven floor tile. Tighten the closet bolts. Grout or caulk the shims in place. Connect the supply line and turn on the angle stop, then check for leaks. Let the grout or caulk dry before using the toilet.

7. Loose Closet Bolt Caps

The closet bolt caps cover the closet bolt, nut and washers. The plastic washers holding the caps in place often fail, leaving loose caps. If the cap fails to remain attached to its base, fill the cap with plumber's putty and press the cap onto the closet bolt. The plumber's putty holds the cap in place without fouling the closet bolt threads. Carefully placing a bead of caulk around the cap edge serves the same purpose.

Attack a toilet clog with a plunger first.

Attack a toilet clog with a plunger first.

8. Clogged Toilet

Nobody likes to flush the toilet and watch the water, and everything else, rise to the rim of the bowl. A complete overflow compounds the problem. Normally water slowly seeps past the clog and the water level in the bowl will slowly fall.

  1. Dislodge debris with a plunger: Position a toilet plunger, a plunger with a bell-shaped end, against the bowl's opening. Firmly force the plunger down. Work the plunger up and down several times before testing the toilet. The plunger forces soft obstructions down the drain.
  2. Dislodge the debris with an auger: If the plunger does not resolve the issue, run a toilet auger down the toilet's drain opening. Turning the auger's handle works the cable around the trap's tight bends. A toilet auger's protective sleeve prevents damage to the inside surface of the bowl. If the obstruction is too large for the toilet's trap, remove the toilet and run the auger up the discharge port. The end of the auger should push the debris back toward the bowl. If the clog has lodged in a drain pipe beyond the toilet, remove the toilet and run a plumber's snake or auger down the drain pipe.
  3. Clear the ventilation: If the toilet gurgles after the water and waste leaves the bowl, check the bathroom's vent stack. The vent pipe lets the bathroom's drain system breath. During the flush water displaces the air in the drain pipe, forcing sewer gasses out the vent pipe. As the water level in the pipe lowers, fresh air returns to the drain system through the vent pipe. Without proper ventilation a toilet will gurgle and have a slow flush. To flush a drain stack, climb on the roof and check the stack's opening for a restriction, such as a bird nest. After removing all debris from the stack's opening, place the end of a garden hose in the vent stack. Open the building's clean-out plug. Turn on the water. Have a helper look down the clean-out opening to verify water flows through the drain. Because the vent stack connects to the toilet's drain, water running down the vent stack will pass the clean-out opening. If water does not pass the clean-out opening, turn off the hose and run a plumber's snake down the vent stack.

9. Slow or Incomplete Flush

This common problem often occurs when water deposits clog the bowl's internal channels or organic buildup forms on the inside of the drain pipe, effectively shrinking the pipe's diameter. This problem mimics a clogged drain issue; however, this type of issue develops slowly over time while a clogged drain usually happens instantly.

  1. Troubleshoot the flush: Pour a bucket of water into the bowl. If the water level rises to the top of the bowl and then slowly drains, suspect a restricted drain pipe. If the bowl flushes normally, expect buildup inside the bowl’s internal passageways. During a normal flush the siphon port, the hole located at the bottom of the bowl, pushes water down the drain; dumping the bucket of water into the bowl mimics this. The small holes under the bowl's rim create the whirlpool effect that cleans the sides of the bowl.
  2. Dissolve debris in blocked passageways: Remove the lid and use a funnel to pour a toilet-care product designed to dissolve water deposits down the overflow tube. These types of products are more environmentally safe than muriatic acid, and they are usually septic safe. Let the toilet sit unused overnight. Repeat this nightly until the toilet flushes normally. Many plumbers would recommend replacing a toilet with completely blocked passages.
  3. Clear an obstructed drain system: Repeat the clogged drain instructions above, starting with a plunger before moving on to the toilet auger and vent check. If that does not solve the issue, pour a drain-care product into the bowl and flush. This type of product eats organic buildup inside the drain pipe. Wait the manufacturer's recommended activation period before testing the toilet.
Dual-flush toilets save water.

Dual-flush toilets save water.

When Should You Replace a Toilet Rather Than Fix It?

Because of their inefficient bowl design, older toilets have a hard time removing waste. Over time, water deposits fill the internal water delivery passageways, creating a persistent slow flush situation. Often these passageways are hard, if not impossible, to clean.

Saving Water With a High-Efficiency Toilet

Older toilets use a lot more water than their modern counterparts. Modern toilets use 1.6 or less gallons per flush. In order to remove all the waste in a single flush, engineers have changed the size and shape of the toilet bowl's internal passageways.

A quick check at a larger hardware store often finds a wide selection of toilets that use 1.28 gallons of water per flush, while maintaining a high flush efficiency rating. Some local municipalities may even offer a rebate when replacing an older toilet with a new high-efficiency toilet.

Upgrading to a Dual-Flush Toilet

Consumers looking to limit water usage often look for a toilet with a dual-flush feature. The dual flush option lets the user choose between a full flush and a partial flush. When the toilet contains solids, the user selects full flush. When the bowl contains only liquids or a small amount of solids, the user chooses the partial flush button.

Typically a full flush uses 1.6 gallons, while a partial flush releases approximately 1.1 gallons. The ability to choose flush options can save hundreds of gallons of water over the toilet's lifespan.

This article is accurate and true to the best of the author’s knowledge. Content is for informational or entertainment purposes only and does not substitute for personal counsel or professional advice in business, financial, legal, or technical matters.

© 2013 Bert Holopaw

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