Calcium Buildup in Toilets

Toilet bowl and bidet in a toilet image by terex from

A backed-up toilet can be a very big nuisance, especially when no amount of plunging seems to be solving the problem. Another cause of a clogged toilet that should be considered is a possible calcium build-up. Calcium deposits are often the culprit of a clogged toilet, and the reason why waste won't pass through in the first place.

Cause of Calcium Deposits

Calcium deposits in toilets are caused by hard water, which is water that is high in mineral content, such as calcium and magnesium. When hard water passes through the plumbing system, the calcium in it will get caught in small nooks and crannies, causing a build-up that can restrict the size of a sewage pipe. As the opening becomes smaller, waste has a more difficult time passing through.

Identifying Calcium Deposits

A simple way to see if your toilet is clogged is to check inside the tank. Most of the time when there is a calcium deposit problem, there will be a build-up within the tank itself, which looks like a white, sometimes light brownish, substance on the inner working parts of the tank. Inside the toilet bowl, a calcium build-up may be a reddish colour from urine and algae infiltration.


To fix a calcium deposit problem in a toilet, try shutting off the water to the toilet and flushing out any water in the tank. Mix 1 gallon of vinegar with 1 gallon of hot water, and pour it into the tank, allowing the mixture to sit for a while. You can also scrub the deposits with a brush to speed up the process, then flush the toilet a few times. The vinegar should work as a natural acid that will help break down the calcium. If this doesn't work, you can try using an auger on the toilet, which may manually dissolve the calcium deposits. If that doesn't work, you may need to get help from a professional.


The easiest way to stop a calcium deposit problem is to prevent it from building up in the first place. Do this by keeping the toilet bowl and toilet tank clean, and occasionally scrubbing where build-up is most likely. Using a water softening device can also help.

Other Possible Issues

A calcium deposit in the toilet may signal other problems with the plumbing. In most cases, toilets share the same sewage pipe, so if you notice a calcium build-up in one toilet, you should check to see that other toilets in the house aren't having the same problem. If other toilets are working fine, then there probably isn't a problem with sewage pipes.

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