Home › A Weak Flush

A Weak Flush

A flush that works but not properly is a different fault from one that does not work at all, and one of its causes is not a fault.

Short version

A toilet that flushes but not properly is usually rim jets blocked with mineral, a water level set too low in the tank, or a chain with too much slack in it. Sometimes it is simply an early low-flow fixture doing what it was designed to do.

Tank and Bowl is a referral service, not a contractor. We connect homeowners with independent contractors. Contractors are required to hold whatever credential their state or municipality demands. Every state page sets out who licenses plumbers there and where to check, so you can confirm before work begins. We carry out no work, we sell no fixtures, we do not set prices, and we never charge homeowners anything — the contractors in our network pay us when we route them a call.

Check the water level before anything else

The tank is designed to release a set volume, and the mark on the overflow tube or the inside wall is where the level should sit. If the fill valve is shutting off early the flush has less water behind it, and the result is exactly the complaint: it goes, but it needs a second one.

This is an adjustment on the fill valve, not a repair.

Then the chain

Slack in the chain means the flapper does not lift fully, drops early, and closes before the tank has emptied. The flush is short rather than weak. It is the same symptom from the opposite cause and it is free to fix.

Then the rim jets, which nobody checks

Water enters the bowl through small holes under the rim, and on hard water they scale up over years. The flush loses its swirl and its force without anything having broken. Running a mirror under the rim shows whether the holes are open.

If your water is hard, the same deposits are forming everywhere in the house, and the rim jets are just where you notice them.

And sometimes it is the specification, not a fault

EPA notes that the Energy Policy Act of 1992 set the maximum flush volume for tank-type toilets at 1.6 gallons per flush, and puts pre-standard models at 3.5 to more than 5.0 gallons. Some of the earliest fixtures built to meet the new limit did it by taking water away rather than by redesigning the bowl, and they flush poorly because of how they were made.

A toilet like that is not repairable into a good one. That is one of the few cases where replacement is the honest answer, and modern fixtures at the same volume or lower do not have the problem.

Source: US EPA WaterSense, tank-type toilet supporting statement; US EPA WaterSense, Residential Toilets.

If the dye test pointed at the flapper, that is a part, not a fixture.Worth saying on the call, because it changes what somebody arrives with. We connect you to a contractor covering your area and you are never charged. Toilets head this site, but any plumbing job is welcome.

Call (888) 525-3450