Why Is My Toilet Slow to Fill?

Have you noticed that your toilet is taking longer to refill after flushing? This is a common toilet issue with several possible causes. Thankfully, none of them are major concerns or costly to correct. Follow this guide to get your slow toilet flowing quickly again. 

How to Address a Slow-Filling Toilet 

Learning why your toilet is slow to fill is step #1 for fixing it. Keep in mind these possible reasons and how to deal with each one. 

Partially Closed Water Supply Valve 

Look behind the toilet for the water supply hook-up attached to the wall. You’ll find a valve connecting to it, which enables you to turn off the water when repairs or full replacement of the tank is needed. Check this valve to make sure it’s completely open. 

Trouble with the Fill Valve or Tube 

The fill valve, which is connected to the top of a vertical tube-shaped part in the toilet tank, manages the water flow into the tank. A toilet fill valve may break down, clog or shift out of alignment after years of use, hindering the tank from filling right. Follow these tips to adjust, unclog or fix the fill valve: 

  • Find the fill valve: Open the toilet tank lid and find the fill valve inside. It’s usually installed 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 connected to the tube. Change the fill valve height if needed by twisting the adjustment knob (found in newer toilets) or use a flathead screwdriver to loosen and adjust (required for older toilets). After that, ensure that the water level is roughly one inch below the top of the overflow tube. 
  • Clean the fill valve: To remove mineral accumulation and other gunk from the valve, first shut off the water in the rear of the toilet and take off the fill cap. Then, slowly turn the water back on, cupping your hand over the valve to avoid getting sprayed. Let the water flow for several seconds to flush out debris. Next, scrub away mineral buildup on the fill cap. If you observe cracks or excessive wear and tear, replace the valve. 
  • Clean the valve tube: Dirt lodged in the valve tube could also be to blame. Turn off the water supply and take off the valve hardware. Then, run a thin wire or bottle brush down the tube. Turn back on the water supply slightly to rinse away the excess residue. Reconnect the valve hardware and confirm if the toilet fills properly. 

Waterlogged Float Ball 

The float ball in older toilet models rises with the water level, shutting the fill valve once the tank is full. If the float ball is damaged or punctured and fills with water, it keeps the tank from filling properly. 

Take off the tank lid and view inside. A partially submerged float ball might be waterlogged. Prior to replacing the ball, check the float arm it’s attached to. If the arm is pointed too low in the tank, bend it up slightly to lift the ball’s height. 

If that fails to solve the issue, you may be able to install a new float ball. Just remember that this is old toilet technology, so it may well be better to upgrade the existing tank hardware or switch out the toilet altogether. 

Blocked Plumbing Vent 

Your home plumbing system uses vents that permit air to enter the pipes. If they are clogged, pressure may build inside of the pipes, preventing the water from flowing. This can, in turn, make your toilet fill at a snail’s pace or even cause the bowl to flood. 

You should grab a ladder and climb up on the roof to look for clogged plumbing vents. Start looking for long, vertical PVC pipes poking up from the roof tiles. Clear away any animal nests, deep snow or other obstructions you notice to guarantee that your plumbing can function as intended. 

Leaky or Blocked Pipe 

If you can’t find anything wrong with the water supply valve, fill valve and tube, float ball or plumbing vents, the slow toilet dilemma could stem from your supply pipes. A problem with the water line itself could prevent your toilet tank from filling appropriately. It’s best to hire a licensed plumber to handle these issues. 

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

When all else fails, turn to Service Experts Heating, Air Conditioning & Plumbing for quality toilet repair in the U.S.. We can figure out the reason why the water flow is so slow and perform the most appropriate repair. If the fixture has come to the end of its useful life span, our company can recommend high-efficiency toilet replacement in the U.S.. We’ll help you decide on the replacement model and install it for you. Rest assured that every job we perform is supported by a 100% satisfaction guarantee! To schedule a visit from us, please call Service Experts Heating, Air Conditioning & Plumbing today. 

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