3 Reasons Why Your Toilet Is Slow to Fill

3 reasons why your toilet is slow to fill
Does it seem like your toilet water is too slow to fill after a flush? This is a common problem for homeowners.

There are a few different reasons why this issue might happen. Fortunately, none are especially serious or expensive to resolve. Identifying the problem can help you apply the correct solution to get the toilet running optimally again as soon as possible.

Read on to learn three common reasons for a slow-filling toilet, how to troubleshoot the problem, and the steps you can take to fix it:

Why Is the Toilet Slow to Fill?

Typically, a toilet tank refills in about a minute. If you notice it’s taking a lot longer, you may have an issue that needs attention.

Here are three possible reasons your toilet water is slow to fill.

1. Water Supply Valve Problem

The water supply valve is a knob protruding from the wall beneath the toilet tank. It controls the rate at which water flows into your toilet tank. If this valve is partially closed or broken, it may be delivering water into your toilet tank too slowly. Additionally, debris can build up in the valve and restrict the flow of water.

Troubleshooting tip: Make sure the valve is fully opened. If a fully opened valve is still not producing the right amount of water to refill the tank, contact a service expert to check the valve for debris buildup or other issues.

2. Waterlogged Float Ball

If your toilet mechanism has a float ball, it sits on top of the water in your toilet tank and controls the amount of incoming water. If the float ball becomes waterlogged, it may prevent your tank from filling properly.

Troubleshooting tip: Remove the toilet tank lid and check the water level. If it’s only partially full or the ball is not floating near the top of the tank, you may have a waterlogged float ball. Fortunately, all you have to do to replace a float ball is pull the old one off of the float arm and replace it.

However, a float ball is old toilet technology. If this mechanism is going bad, consider replacing your inner toilet parts with modern components.

3. Fill Valve Tube Issues

A fill valve is attached to the vertical tube-shaped device inside your toilet tank. Its job is to control the water level within the tank. These valves can wear down, clog, or shift out of alignment. Each of these issues can prevent the toilet from filling properly.

Troubleshooting tip: If you’ve determined the problem is not the water supply valve or a waterlogged float ball, take a closer look at the fill valve. Inspect the valve for signs of wear and tear or incorrect positioning inside the tank. It should be mounted on the left side of the tank with a tailpiece extending through the bottom of the tank, where it attaches to the supply tube and shut-off valve.

How to Fix a Slow-Filling Toilet

Time required: About 30 minutes

Materials needed: Gloves, screwdriver, scrub brush, wire or tube brush

Now that you have a better idea of what may be causing your toilet tank to fill slowly, here are the actual steps you can take to fix the problem.

Open the Water Supply Valve

  • In some cases, the water supply valve may have been partially closed. Check to make sure the valve is open all of the way.

Adjust the Fill Valve

Follow these steps to adjust the fill valve:

  • Remove the tank lid and find the fill valve—it’s usually on the left side of the tank.
  • Make sure the fill valve is securely and evenly attached to its tube.
  • For older toilets, use a flathead screwdriver to loosen the adjustment screw and raise the fill valve to let more water into the tank.
  • For newer toilets, turn the fill valve adjustment knob with your hand to let more water into the tank.
  • For all toilets, make sure the water level is about an inch below the top of the overflow tube.
  • Flush the toilet and then check to see if the tank fills at the right rate and with the right amount of water.

Clean the Fill Valve

Is there mineral buildup or debris on the valve? Here’s how to clean it:

  • Shut off the toilet’s water supply and remove the tank lid.
  • Remove the screws on top of the fill valve and remove the fill cap.
  • Slowly turn on the water supply, cupping your hand over the valve to avoid getting sprayed.
  • Let the water flow freely through the valve to flush out debris and buildup.
  • Turn the water supply off after letting it flow for a few seconds.
  • Flip the fill cap and find the washer. Remove it with a screwdriver and gently scrub away mineral buildup.
  • If you notice cracks, replace the fill valve.
  • Finally, replace the valve, secure it with the screws, and turn the water on to see if you’ve fixed the problem.

Fix or Replace a Waterlogged Float Ball

  • Check to see if the float arm attached to the float ball is fixed too low in the tank. If that’s the case, bend the arm slightly upward so the ball rises higher in the tank, allowing more water to flow into the tank.
  • If this doesn’t work and you still think the float ball is the issue, you may need to install a replacement float ball or contact your local plumber about upgrading to a newer style mechanism.

Fix a Valve Tube Problem

To fix a clogged valve tube, you must clean debris out of the tube.

  • Shut off the water supply.
  • Remove the hardware from the valve.
  • Use a slim wire or bottle brush to clean out the tube.
  • Open and shut the water supply valve a few times to flush away any remaining residue and clear all of the clogs.
  • Replace the hardware and the tube and check to see if the toilet begins to fill properly after flushing.

If the tube has holes, tears, or looks worn or damaged, install a replacement valve tube

Choose Mr. Rooter® Plumbing for Toilet Repair and Replacement Services

Want to save time, avoid troubleshooting hassles, and get reliable toilet repair from the pros? The team of licensed plumbers at your local Mr. Rooter Plumbing can provide you with the toilet replacement and repair services you need. Call us today or request an estimate online to get started.