Home / News & Media / Toilet Plumbing Tips

DIY Fixes for a Toilet Not Flushing Properly

11 min read • April 12th, 2024

Heil Plumbing

Toilet not flushing properly no matter how many times you jiggle the handle? It’s a common yet frustrating issue. The causes can range from a slow-filling tank to a toilet that runs continuously, wasting water and your patience. Understanding what’s behind this pesky problem is the first step toward a solution.

The Annoyance of a Toilet Not Flushing Properly

Toilets are more complex than they appear, with several components working together to ensure a smooth flush. From the fill valve to the flapper, each part plays a pivotal role. While fixing some issues requires professional help, many issues can be resolved with a little old-fashioned DIY know-how.

In this blog, we’ll guide you through diagnosing and fixing common flushing problems. Whether your toilet is running continuously, filling slowly, or not flushing at all, we’ve got you covered. Watch the video below and keep reading to learn:

  • How to identify the root cause of flushing issues
  • Step-by-step guides for replacing the fill valve and flapper
  • Tips for adjusting the float to improve flushing efficiency
  • Inspecting and addressing overflow tube issues to prevent leaks

Are you ready to tackle your toilet troubles? Let’s dive in and get your bathroom back to its best, one flush at a time.

Essential Tools and Replacement Parts for Fixing Your Toilet (0:13-1:26)

When it comes to tackling toilet repair, the right tools and parts can make all the difference. Before you start, ensure you have the following items ready:

  • Adjustable Wrench or Pliers: A must-have for loosening and tightening various nuts and bolts.
  • Side Cutters or Box Cutter: Useful for cutting parts to size, such as the refill tube.
  • Bucket and Towel (or a Wet/Dry Vacuum): While a wet/dry vacuum is excellent for removing water quickly, a simple bucket to catch drips and a towel for drying off can also do the trick effectively.
  • New Fill Valve: Typically, a Fluidmaster Pro 45 is a reliable choice due to its availability, reliability, and ease of installation.
  • Toilet Flapper: Ensure it’s compatible with your toilet model. A universal flapper often works, but specific types, like those for Kohler toilets, might be needed.
  • Toilet Supply Line: Opt for a longer length than you think you’ll need; it’s easier to work with and can be adjusted to fit.

How Does a Toilet Work: Understanding Your Toilet’s Mechanics (2:15-2:58)

A basic understanding of how your toilet operates can illuminate why issues arise. At the heart of your toilet’s flushing mechanism are two critical components: the fill valve and the flapper. When you push the flush lever, the flapper lifts, allowing water to flow from the tank into the bowl, creating the flush. After releasing the lever, the flapper should return to its position, resealing the tank so it can refill for the next use. The fill valve, in turn, senses the drop in the tank’s water level and refills it, shutting off once the correct water level is restored.

Bottom line: the flush lever, the fill valve, and the flapper work all together to ensure your toilet flushes and refills efficiently. However, if any part malfunctions, the result will be your toilet not flushing properly.

Identifying the Root Cause: Slow Filling, Running Toilets, and More (3:29-4:25)

To effectively tackle toilet repair, first identify the root cause of the problem.

Common toilet problems:

  • Slow Filling Toilet Tank: This issue can stem from a clogged or malfunctioning fill valve. Sediment build-up or wear and tear over time can restrict water flow into the tank.
  • Toilet constantly running: A constantly running toilet is often due to a faulty flapper that doesn’t seal properly. This allows water to leak from the tank into the bowl continuously.
  • Weak Flush: A weak or incomplete flush can indicate a blockage in the toilet’s internal trap or pipes, or issues with the tank’s water level being too low.

Diagnosing a toilet not flushing properly:

  1. Inspect the Flapper: Remove the tank lid, flush the toilet, and watch the flapper. If it doesn’t form a tight seal, water will leak, causing the fill valve to run continuously to keep the tank filled.
  2. Check the Fill Valve for Blockage:
    • Turn off the water supply
    • Disassemble the fill valve (paying attention to how it fits together, so you can reassemble it)
    • Look for debris
    • Clean as necessary and reassemble OR replace the valve if damaged (see below for instructions)
  3. Check for Blockages: If flushing power is weak, use a plunger or a plumber’s snake to clear any blockages in the bowl or pipes.

Replacing the Fill Valve: A Detailed Guide (4:25-8:03)

A malfunctioning fill valve is a common culprit behind a slow-filling toilet tank. Replacing it is a straightforward process that can significantly improve your toilet’s efficiency. Here’s how to do it:

how to install a toilet supply line: with a toilet not flushing properly, a plumber detaches a toilet water supply line from the water shut off valve
  1. Turn off the water supply: Locate the shut-off valve near the base of your toilet and turn it clockwise to shut off the water (if you want to be extra cautious, find your home’s water shut-off valve). This prevents any more water from entering the tank while you work.
  2. Prepare the area: Take the toilet tank top off and place a towel behind the toilet, under the supply line to catch any dripping water. Also, you will want a small bucket on hand.
  3. Empty the Tank: Flush the toilet to drain as much water as possible from the tank. Look inside the toilet tank to confirm that the water supply is truly off (and not filling the tank back up). For any remaining water left in the tank, use a sponge or towel to soak it up and wring it out into your bucket.
  4. Loosen the nut connecting the supply line to the shut-off valve: Use an adjustable wrench or pliers to loosen the nut connecting the supply line to the water shut-off valve. Warning: Do not yank on the nut too hard so you don’t accidentally break the shut-off valve and flood your bathroom! If the nut won’t budge, use a second wrench or set of pliers, to hold the water shut-off valve in place and to provide counter-pressure so that you can loosen the nut without breaking the valve. Watch the video at 5:55 to see how we loosen the nut carefully. Leave the supply tube connected to the shut-off valve for now.
  5. Loosen the nut connecting the supply line to the fill valve: Unscrew the wingnut connecting the water supply line to the fill valve in the tank, usually found underneath the tank. (Note: if your nut is plastic, loosen it by hand.)
  6. Disconnect the supply line: Taking the water supply line in both hands, hold the shut-off valve in place and gently wiggle the top of the supply line to disconnect it from the toilet tank and the fill valve. Watch the video at 7:30 to see how we remove the supply line carefully.
  7. Place a bucket underneath the old fill valve
  8. Remove the old fill valve: Once loose, lift the old fill valve out from the top and any remaining water should drain out into your bucket.
  9. Install the new fill valve: Insert the new fill valve into the hole where the old one was, ensuring the rubber washer provided is placed at the bottom of the fill valve, inside the tank. This washer ensures a watertight seal. Watch the video at 9:12 to see how to assemble and install the new fill valve.
  10. Secure the fill valve: From underneath the tank, screw the new wingnut onto the fill valve’s threads to secure it in place, tightening by hand. Warning: Tighten it enough to ensure a leak-proof fit but be careful not to overtighten, as this could crack the porcelain.
  11. How to install a toilet supply line: Attach the supply line back to the bottom of the new fill valve, tightening by hand, and tightening the connecting nut with an adjustable wrench or pliers 1/4 turn past hand-tight.
  12. Adjust the fill valve (if necessary): Some fill valves allow for height adjustment to ensure the correct water level in the tank. Follow the manufacturer’s instructions to adjust the height as needed.
  13. Turn on the water supply: Once everything is secure, turn the shut-off valve counterclockwise to restore water to the tank (or turn your whole house shut-off valve back on if you shut it off instead). Watch the tank fill and ensure the new fill valve shuts off the water at the correct level.
  14. Test the flush: After the tank has filled, flush the toilet to ensure everything is working correctly. The tank should refill to the proper level quickly and stop.

How to Replace a Toilet Flapper (8:44-16:06)

A faulty flapper is often the culprit behind running toilets. To replace it:

  1. Turn off the water: Just like with replacing the fill valve, start by turning off the water supply to your toilet to prevent more water from entering the tank. (You may prefer to turn off your home’s emergency water shut off. Just note that this will shut off water everywhere in your home.)
  2. Prepare the area: Take the toilet tank top off.
  3. Flush and empty the tank: Flush your toilet to drain the water from the tank. Use a sponge or towel to remove any remaining water, ensuring a dry work area. If your toilet tank fills back up, then your water supply is not truly off, and you should repeat Step 1 (tightening the shut-off valve a little further without over-tightening it). If your toilet tank continues to fill back up, you may have to get a trusted local plumber to come replace your shut-off valve.
  4. Remove the old flapper: Detach the old flapper from the flush valve in the toilet tank. It’s usually connected by two ears on the sides that clip off easily. Also, disconnect the chain from the flush lever.
  5. Clean the valve seat: Before installing the new flapper, clean the valve seat to ensure a good seal. Remove any build-up or debris that might prevent the flapper from sealing properly.
  6. Install the new flapper: Attach the new flapper to the flush valve. Ensure it’s centered and securely attached to the valve’s ears. Connect the chain to the flush lever, leaving a little slack to ensure it can lift fully when the toilet is flushed.
  7. Adjust the chain length: The chain length is crucial for proper flushing. Too much slack, and the flapper won’t lift enough to allow a full flush. Too little, and the flapper won’t seal properly, causing the toilet to run. Adjust as needed for optimal performance. Even the pros sometimes need to make a few adjustments before finally getting the right chain length for the optimal flush.
  8. Turn on the water and test: Turn the water supply back on and let the tank refill. Flush the toilet several times to ensure the flapper lifts and reseals correctly, and the toilet flushes properly.
  9. Check for leaks: After replacing the flapper and the toilet is back in operation, watch for your toilet flapper leaking. If the toilet continues to run, further adjustments to the flapper or chain may be needed.
plumber addresses toilet flushing problems with a Fluidmaster Pro 45 by adjusting the water level for an optimal flush

Adjusting the Water Level for Optimal Flushing

Ensuring your toilet’s water level is correctly adjusted is key to achieving efficient flushing while conserving water. Here’s how to adjust the water level in your toilet tank:

  1. Locate the water level mark: Inside your toilet tank, find the manufacturer’s water level mark. This mark indicates the ideal water level for your specific toilet model.
  2. Inspect the float: The float regulates the water level in your tank. It can be a ball float connected by an arm to the fill valve or a cup float that moves up and down along the fill valve shaft.
  3. Adjust the float:
    • For a ball float: Adjust the water level by turning the screw on the arm of the fill valve or by bending the arm gently to raise or lower the float.
    • For a cup float: Slide the float up to increase the water level or down to decrease it. This is usually done by pressing a release button or pinching a clip on the float to allow it to move freely.
  4. Test the adjustment: Flush the toilet to see if it refills to the desired level. You might need to repeat the adjustment process a few times to get it just right.
  5. Check for continuous flow: If the water continues to run after adjustment, ensure the float isn’t sticking, or the fill valve isn’t obstructed. Sometimes, small adjustments can make a significant difference.
  6. Final check: Once you’re satisfied with the water level, do a final flush to ensure everything operates smoothly and the tank fills to the correct level.

Inspecting and Addressing Overflow Tube Issues

An often overlooked component in toilet maintenance is the overflow tube. This part is crucial for preventing water from spilling over the tank if it fills too high.

plumber identifies toilet overflow tube issues

Here’s how to inspect and address issues with the overflow tube:

  1. Identify the overflow tube: Inside your toilet tank, the overflow tube is usually a tall, cylindrical component standing upright near the center. It’s directly connected to the flush valve.
  2. Check for damage: Look for any cracks or signs of wear on the tube. A damaged overflow tube can lead to leaks or improper water levels in the bowl, affecting flushing efficiency.
  3. Assess the water level: The water in your tank should never reach the top of the overflow tube. If it does, it’s a sign that your fill valve needs adjustment. The water should stop filling about an inch below the top of the tube.
  4. Adjust if necessary: If the water level is too high, adjust the fill valve to lower the tank’s water level. This adjustment varies by the type of fill valve but typically involves either a screw adjustment or sliding a clip along a rod. (See above OR watch the detailed video, where we cover this).
  5. Replace if damaged: If your overflow tube is cracked or damaged, it will need to be replaced to ensure proper function. To replace it, you’ll likely need to remove the flush valve, as most overflow tubes are attached to or part of this component.
  6. Test the flush: After any adjustments or replacements, flush your toilet to ensure everything is working correctly. Watch the water level in the tank to make sure it fills properly and stops before reaching the overflow tube.

FAQs: Solving Other Toilet Flushing Problems

  1. Why does my toilet randomly start running?
    • This is often due to a slow leak from the tank into the bowl, usually caused by a faulty flapper or fill valve. Inspect these components again and ensure they’re properly installed and sealing correctly.
  2. Can I use any flapper or fill valve for my toilet?
    • While many toilets can use universal replacements, it’s best to check the manufacturer’s recommendations for your specific model to ensure optimal performance and fit.
  3. How often should I replace toilet tank components?
    • It’s a good practice to inspect your toilet’s internal components annually and consider replacing the flapper and fill valve every 3-5 years, or sooner if you notice signs of wear or leaks.
  4. What should I do if my toilet won’t stop running after replacing the parts?
    • Double-check the installation of the new components. Make sure the flapper is sealing properly, and the fill valve is adjusted to the correct height. If problems persist, there might be an issue with the tank’s seal to the bowl. Contact a trusted local plumber if you need more in-depth troubleshooting.
  5. Why is there a low water level in the toilet bowl?
    • A low water level in the bowl can be caused by clogs in the vent pipe, affecting the flow and vacuum of flushing. It could also be due to improperly adjusted water levels in the tank.

When to Call a Professional

While many toilet issues can be diagnosed and fixed with a little DIY know-how, there are times when calling in a professional is the best course of action. Complex problems, such as internal leaks, structural damage to the toilet, or persistent issues that don’t resolve with standard fixes, may require the expertise and tools of a skilled plumber.

Signs you might need professional help include:

  • Persistent leaks after replacing the flapper and fill valve
  • Cracks in the toilet bowl or tank
  • Frequent clogs that aren’t resolved with a plunger or snake
  • Unusual noises that persist from the tank after adjusting the fill valve and flapper

Attempting to fix these issues on your own can sometimes lead to further damage or inefficiency. Professionals can diagnose and solve problems more efficiently, thanks to their experience and specialized tools.

Heil Plumbing’s Expert Services

If you’re in the Baltimore or D.C. area and facing toilet troubles beyond a simple DIY fix, Heil Plumbing is here to help. Our team of experienced professionals can handle the most complex plumbing jobs, ensuring your toilet repairs are done right the first time. Whether you need assistance in Howard County, Anne Arundel County, Baltimore County, or Montgomery County, we’ve got you covered.

You don’t have to live with a toilet that doesn’t flush properly.


Heil Plumbing Team

8177 Mission Rd Jessup, MD, 20794, United States

(410) 799-7727

Schedule Service


related articles

11 min read • April 26th, 2024

The Best Water Heater Brand According to Plumbers

When it comes to essential home appliances, your water heater ranks high on the list, impacting everything from your morning routine to your utility bills. But not
Heil Plumbing
Toilet Plumbing Tips
11 min read • April 12th, 2024

DIY Fixes for a Toilet Not Flushing Properly

Toilet not flushing properly no matter how many times you jiggle the handle? It’s a common yet frustrating issue. The causes can range from a slow-filling tank
Heil Plumbing
contemplating traditional vs trenchless sewer repair pros and cons
11 min read • March 29th, 2024

What Is Trenchless Sewer Repair and What Are the Pros and Cons

When facing sewer line issues, homeowners dread the thought of their yards being dug up and they struggle to understand why sewer line replacement is so expensive.
Heil Plumbing