How to Fix a Running Toilet: A Cedar Park Homeowner's Step-by-Step Guide

A running toilet is one of the most common — and most annoying — plumbing problems in Cedar Park homes. Beyond the constant noise, a running toilet can waste 200 gallons of water per day, adding up to over $60 per month on your Williamson County water bill. The good news? Most running toilets can be fixed in under 30 minutes with basic tools.

What Causes a Toilet to Run?

Before you start fixing, it helps to understand what's happening inside your toilet tank. When you flush, the flapper lifts to release water from the tank into the bowl. Once the tank empties, the flapper seals shut and the fill valve refills the tank to a preset level. A running toilet means one of these components isn't doing its job.

The three most common culprits are a worn flapper, a faulty fill valve, or an improperly adjusted float.

Fix #1: Replace the Flapper

This fixes the problem about 70% of the time. The flapper is the rubber seal at the bottom of your tank. Over time, especially with Cedar Park's hard water, the flapper warps, cracks, or accumulates mineral deposits that prevent a tight seal.

To replace it: turn off the water supply valve behind the toilet, flush to empty the tank, unhook the old flapper from the overflow tube, and snap the new one in place. Universal flappers cost $5–$8 at Home Depot or Lowe's (both have Cedar Park locations on 183). Turn the water back on and test.

Fix #2: Adjust the Float

If the water level in your tank is too high, water continuously flows into the overflow tube, causing the toilet to run. You'll see a float (either a ball on an arm or a cylindrical float that slides on the fill valve). Adjust the float so the water level sits about 1 inch below the top of the overflow tube. Most floats have an adjustment screw or clip.

Fix #3: Replace the Fill Valve

If the flapper and float are fine but your toilet still runs, the fill valve itself is likely worn out. Fill valve replacement kits cost $8–$15 and come with instructions. This is a slightly more involved repair that requires disconnecting the water supply line, but it's still a manageable DIY project for most homeowners.

When to Call a Professional

If you've tried all three fixes and your toilet still runs, there could be a more serious issue like a cracked tank, a warped flush valve seat, or an issue with your home's water pressure. Cedar Park Home Repair handles toilet and plumbing repairs daily across Leander, Round Rock, Avery Ranch, and all surrounding communities — we can diagnose and fix the problem quickly, usually in a single visit.

How Much Does Toilet Repair Cost?

Most toilet repairs in the Cedar Park area cost between $75 and $200 for professional service. For a full breakdown of handyman pricing, see our 2026 Handyman Cost Guide for Cedar Park.