Why Is My Toilet Slow to Fill?

Is your toilet tank filling more slowly than usual? This is a common toilet issue with several possible causes. Luckily, none of them are major concerns or expensive to deal with. Follow this guide to get your slow toilet working properly again. 

How to Address a Slow-Filling Toilet 

Finding out why your toilet is slow to fill is the first step toward fixing it. Consider these possible reasons and how to handle each one. 

Partially Closed Water Supply Valve 

Check behind the toilet for the water supply hose connected to the wall. You’ll see a valve connecting to it, which enables you to turn off the water when your toilet is being repaired or replaced. Check this valve to make sure it’s completely open. 

Issues with the Fill Valve or Tube 

The fill valve, which you’ll find close to the top of a vertical tube-shaped part in the toilet tank, controls the water flow into the tank. A toilet fill valve may break down, clog or reposition out of alignment after years of use, hindering the tank from filling properly. Follow these instructions to adjust, unclog or fix the fill valve: 

  • Locate the fill valve: Open the toilet tank lid and find the fill valve inside. It’s normally mounted on the left side with a tailpiece extending through the bottom of the tank and linking to the supply tube and shut-off valve. 
  • Adjust the fill valve: Be sure that the fill valve is secure and evenly fastened to the tube. Adjust the fill valve height if needed by turning the adjustment knob (typical to newer toilets) or loosening the adjustment screw with a flathead screwdriver (required for older toilets). Next, check that the water level is roughly one inch below the top of the overflow tube. 
  • Clear debris from the fill valve: To eliminate mineral buildup and other debris from the valve, first shut off the water in the back of the toilet and remove the fill cap. After that, slowly turn the water back on, cupping your hand over the valve to avoid getting sprayed. Allow the water to flow for 15-20 seconds to flush out dirt. Next, scrub away mineral buildup from the fill cap. If you notice cracks or substantial wear and tear, replace the valve. 
  • Clean the valve tube: Dirt inside the valve tube could also be the culprit. Shut off the water supply and take off the valve hardware. Next, run a slim wire or bottle brush into the tube. Turn back on the water supply slightly to clean away the leftover residue. Re-install the valve hardware and confirm if the toilet fills faster now. 

Waterlogged Float Ball 

The float ball in older toilet models rises with the water level, sealing the fill valve once the tank has filled. If the float ball takes on water, it keeps the tank from filling correctly. 

Pull up the tank lid and look inside. A partially sunken float ball may be waterlogged. Before running out to buy a new ball, examine the float arm it’s secured to. If the arm is fixed too low in the tank, bend it up slightly to raise the ball’s height. 

If that does not do the trick, then it might be time to just replace the component entirely. Just remember that this is old toilet technology, so it might possibly be better to upgrade the existing tank parts or change out the toilet entirely. 

Plugged Plumbing Vent 

Your home plumbing system features vents that allow air to enter the pipes. If they end up clogged, pressure may build within the pipes, blocking the water from flowing. This can, in turn, make your toilet slow to fill or even cause the bowl to overflow. 

You should grab a ladder and climb up on the roof to search for clogged plumbing vents. Start looking for long, vertical PVC pipes poking up from the shingles. Get rid of any animal nests, deep snow or other obstructions you see to help your plumbing work as intended. 

Leaky or Blocked Pipe 

If there’s nothing apparently wrong with the water supply valve, fill valve and tube, float ball or plumbing vents, the slow toilet problem could stem from your supply pipes. A problem with the water line itself could restrict your toilet tank from filling correctly. It’s safest to hire a licensed plumber to tackle these issues. 

Schedule Toilet Repair with Service Experts Heating, Air Conditioning & Plumbing 

If these tips did not handle your issue, look to Service Experts Heating, Air Conditioning & Plumbing for dependable toilet repair in the U.S.. We can identify the reason why this is happening and perform a cost-effective repair. If the fixture has hit the end of its typical life span, our team can recommend high-efficiency toilet replacement in the U.S.. We’ll help you find the replacement model and install it for you. Relax knowing that every job we perform is backed by a 100% satisfaction guarantee! To schedule a visit from us, please contact Service Experts Heating, Air Conditioning & Plumbing today. 

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