Common Toilet Problems and When to Call a Plumber

Toilets are the most frequently used plumbing fixture in your home, and they are generally reliable. But when something goes wrong, it demands attention — a running toilet wastes water around the clock, a toilet that will not flush disrupts your household, and a leak at the base can damage flooring and subfloor. Some toilet problems are straightforward to fix yourself. Others require professional help to diagnose and repair properly.

Running Toilet

A toilet that runs continuously or cycles on and off by itself is usually caused by a faulty flapper valve at the bottom of the tank. The flapper creates a seal that holds water in the tank between flushes. When the flapper warps, cracks, or collects mineral deposits, it no longer seals properly and water leaks slowly from the tank into the bowl, triggering the fill valve to replenish the tank repeatedly.

Replacing a flapper is a simple repair most homeowners can do — flappers are inexpensive and available at any hardware store. If replacing the flapper does not stop the running, the fill valve itself may be faulty and needs replacement, which is still a manageable project but slightly more involved.

Weak Flush

If your toilet flushes but the bowl does not clear fully or the flush feels weak, the most common causes are clogged rim jets (the small holes under the rim that direct water into the bowl), a low water level in the tank, or a partially blocked drain line.

Cleaning the rim jets with a small brush or wire can restore full flushing power. Adjusting the float to raise the tank water level is another easy fix. If neither helps, a partial blockage in the drain line below the toilet may be restricting flow and requires professional clearing.

Leaking at the Base

Water appearing at the base of the toilet when you flush almost always means the wax ring seal between the toilet and the drain flange has failed. The wax ring creates a watertight seal that prevents waste water from leaking onto the floor and sewer gas from entering your home.

Replacing a wax ring requires removing the toilet, scraping off the old ring, setting a new one, and reinstalling the toilet with proper alignment and bolt tension. While conceptually simple, the weight of the toilet and the importance of proper alignment make this a job best done by a professional — an improperly set wax ring will leak again.

Persistent Clogs

Occasional clogs from excess toilet paper or waste are normal and easily resolved with a plunger. But if your toilet clogs frequently, there may be a deeper issue: a partial blockage in the drain line, root intrusion in the sewer lateral, low-flow toilet design that cannot handle your household's needs, or objects lodged in the toilet trap that snag waste.

A professional can use a closet auger to clear deeper blockages and a camera to inspect the drain line for structural problems. If an older low-flow toilet clogs constantly despite a clear drain line, upgrading to a modern high-efficiency toilet with better flushing engineering is often the lasting solution.