If you hear water trickling long after a flush or notice your toilet tank refills on its own, you are dealing with a running toilet. It is one of the most common plumbing calls we get at Collins Comfort Masters, and understanding the root cause can save you serious money on your water bill, especially here in Tempe where every gallon counts.
Most running toilet problems come from a handful of parts inside the tank. Here is a quick reference before you dive in:
A toilet is "running" when water flow does not fully stop after a flush. You might hear a constant trickling sound, notice the tank refills by itself, or see water visibly moving in the toilet bowl without anyone touching the toilet handle. In the Tempe and Phoenix area, many homeowners first notice it when their water bill spikes.
The main common causes include:
These are the common reasons plumbers in our area get called, and nearly all of them involve parts inside the tank, not the drain line. The sections below walk through how to identify each problem and what you can adjust or replace to fix it.
When you press the toilet handle, it pulls on a chain attached to the flapper. The flapper lifts off the flush valve opening, and water rushes from the tank into the toilet bowl. Once the tank empties, the flapper drops back down to create a seal, and the fill valve opens to let fresh water from the water supply refill the tank.
Here are the key parts in plain language:
In most Tempe homes, these parts are plastic and rubber. Our hard water and hot conditions break them down faster than you might expect. When any piece fails to seal or shut off correctly, the result is a running toilet and wasted water.
The flapper and flush valve form the main seal between the tank and the toilet bowl. A bad seal here is one of the most common causes of a constantly running toilet.
The toilet flapper sits over the flush valve opening at the bottom of the tank. When it is in good shape, it holds water until you flush. Over time, though, rubber warps from age. In Tempe's hard water, mineral buildup coats the surface, and small cracks or misalignment develop. A worn flapper can cause a toilet to run continuously because a faulty flapper seal can leak water into the toilet bowl, slowly lowering the tank level and triggering the fill valve.
Sometimes the problem is the flush valve itself. If the plastic ring the flapper seals against is rough, pitted, or cracked, even a brand new flapper cannot form a tight seal.
To check, try the food coloring test. Use food coloring to check for flapper leaks: add a few drops to the tank, wait 15 to 20 minutes without flushing, and if color appears in the bowl, the flapper or flush valve is leaking.
Replacing a flapper typically takes 10 to 20 minutes and costs under $20 at any hardware store. Check the flapper for cracks or misalignment first. If the flush valve body is damaged or the toilet model is older with hard-to-find parts, a professional plumber from Collins Comfort Masters should handle the valve replacement.
Even when the flapper and flush valve are fine, the toilet can still run if the chain or handle keeps the flapper from closing all the way.
The chain connects the toilet handle to the flapper. If the chain is too short, it holds the flapper valve partially open, allowing water to leak into the bowl. If it is too long, slack can tangle under the flapper and prevent it from seating. Adjust the chain connecting the flapper to the flush handle so there is about half an inch of slack when the flapper is closed.
Old or corroded handles and flush rods sometimes get stuck in the down position, keeping the flapper lifted and water constantly running into the bowl. If tightening a loose handle nut does not help and internal metal parts are badly corroded, it is worth calling a plumber to swap the assembly rather than fighting with it.
The fill valve and float work together to refill the tank and shut the water off. When they are misadjusted or failing, the toilet may never stop running.
The fill valve connects to your home's water supply and controls how much water enters the tank after each flush. Replace the fill valve if it leaks or is faulty and you hear constant hissing or see water spraying from the top. Fill valve malfunctions can lead to nonstop toilet running.
The float ball (or float cup in newer toilets) rides up with the rising water level and signals the fill valve to shut off. If the float is set too high, water will spill into the overflow tube, and the tank never stops trying to fill. The float controls the water level in the tank, so adjusting the float can prevent water from overflowing.
To test, lift the float arm by hand while the tank fills. If water does not shut off when you lift the float, the fill valve is likely worn internally or stuck. Adjust the float to lower the water level in the tank so it sits about one inch below the overflow tube. That is where the water level should be. If basic adjustments do not help, full fill valve replacement is best handled by a professional plumber for many homeowners.
The overflow tube prevents water from spilling over the tank by directing excess water into the toilet bowl. But if water is constantly flowing into it, the toilet continues to run non-stop because the fill valve keeps trying to replace what is lost.
To spot overflow tube problems, remove the tank lid and watch whether water is right at the top of the tube or pouring over the edge. The overflow tube should be 8 to 12 inches above the tank bottom. If it has been cut too short, cracked, or damaged, water spills into the bowl before reaching the correct level.
Often the root cause is not the tube itself but an incorrectly adjusted fill valve or float that is set too high. Water spilling into the overflow tube causes continuous running. More advanced repairs like replacing a cracked overflow tube or reconfiguring the flushing mechanism are good reasons to call Collins Comfort Masters so a technician can stop the problem and inspect for other wear.
While flappers and fill valves cover most cases, some running toilets in the Tempe and Phoenix area come from less obvious sources.
Do not ignore persistent or hard-to-identify running issues. They can point to larger plumbing problems beyond just the toilet parts.
Many Tempe homeowners can safely handle a few quick checks. No special tools needed.
Some running toilet problems are straightforward, but repeated issues or complex causes can waste water and money if not properly diagnosed. A professional plumber can resolve underlying plumbing issues that simple part swaps cannot.
Call Collins Comfort Masters when you experience:
Our plumbers will inspect the flush valve, flapper, fill valve, float, overflow tube, and water supply connections, then test the system under actual water pressure. Professional plumbers have the tools and expertise for repairs that go beyond basic part replacement.
We serve Tempe, Phoenix, and nearby communities, offer emergency service for severe leaks, and back plumbing repairs with our "No Worry" guarantee. Contact us as soon as you notice a constantly running toilet. Stopping the water flow quickly helps you avoid higher water bills in the Arizona desert climate.
Absolutely. A constantly running toilet can waste hundreds of gallons per day. In the Phoenix metro area with tiered water rates, even a small trickle can add up to thousands of gallons over a month. A constant leak can add around $300 a year to water bills. Catching and fixing the problem quickly is far cheaper than ignoring a slightly higher bill for several cycles.
Intermittent running is usually safe in the short term, but it is a sign of a leak or worn part that will not fix itself. Those "ghost flushes" where the tank refills on its own typically come from slow leaks at the flapper or flush valve. If you notice any water outside the toilet at the base or supply line, stop using it and call a plumber immediately.
In a hard-water area like Tempe and Phoenix, rubber and plastic parts such as flappers often need replacement every 3 to 5 years. Fill valves may last longer, but once they begin to hiss, whistle, or cause running, replacement is usually more cost-effective than repeated adjustments. During a routine visit, a Collins Comfort Masters plumber can evaluate components and recommend proactive replacements.
Yes. High water pressure is a less obvious but real cause. It can prevent fill valves from sealing properly and wears them out faster. If you hear banging pipes, see frequent fixture leaks, or have multiple toilets with tube problems, ask a plumber to measure your pressure. Collins Comfort Masters can install or adjust a pressure-reducing valve to protect fixtures throughout your home.
If your toilet is several decades old, has repeated running issues, or uses much more water than modern models that run on about 1.6 gallons per flush, replacement is often the smarter long-term choice. New toilets feature updated flush valve and fill valve designs that reduce the chance of a toilet running constantly. Collins Comfort Masters can help you compare repair versus replacement costs and install a toilet that fits your bathroom, budget, and water-saving goals.