How much can a running toilet increase water bill?

The end of the month always causes fear because of the billing period for a household’s basic utilities. Not paying the water bill is not an option. Water is one of the most necessary resources in anyone’s daily life. That means that sometimes we waste it without realizing it.

Flushing the toilet uses a certain amount of water according to the capacity of the tank. If there is a leak in the flushing system, the tank will try to fill up again and again as the water is wasted. How much water can be wasted if my toilet is broken?

What is the process of flushing?

The process of flushing toilets has not evolved that much over the years so this problem can happen with either an older toilet or a modern toilet. The flushing process works by pulling the lever or pressing the flush button.

The lever activates using a chain, the flapper at the bottom of the tank, which, when pulled, opens to flush the water. After that, the water is filled back into the tank cistern, which raises the float. When the float is already up, the water access is closed.

The float must reach a certain level, meaning that the tank has been filled, so if there is a leak, the float will never reach the level needed, and the amount of water flushed out will be almost uncountable.

The Cost of a Running Toilet

Maybe it doesn’t sound so bad to throw away a little bit of water because of a small leak; this happens because we don’t see the amount of water we are consuming, just trying to fill a tank that won’t. To show us the seriousness of the issue, let’s translate it into accounting measures.

A leaky toilet wastes a considerable amount of water. It is estimated to be like filling thousands of gallons of water monthly. If we translate that into money, it represents an extra $200 in wasted water per month.

This case of extreme leakage represents $2500 of money spent annually on water waste due to a severe leak.

A smaller leak is estimated to represent about 6,000 gallons of water per month, meaning an additional $70 would appear on the monthly water bill for the water wasted. On an annual basis, this represents an extra $1000 per year.

How Do I Detect a Toilet Leak?

The toilet flushing system normally beeps on the water load. That means you can hear if the toilet is malfunctioning. You can hear the constant sound of the tank filling because the leak draws water into the toilet bowl.

If there are suspicions of a leak, a simple way is to put some non-toxic food coloring in the toilet tank. Then wait about 10-20 min before flushing. If you open the toilet bowl’s lid, you can see water with dye in it, which means there is a leak.

What is the science of this test? If there is no leak, the colored water should be all in the flush and down into the toilet bowl when the lever is lowered. However, if there is a leak, the water will seep into the bowl little by little, and you can easily tell whether the toilet is leaking.

How to fix it

We already know how much water we may be wasting and how much the leak represents monetarily. We also know how to detect whether there is a leak or not. Now comes the most important part. Fixing this water problem.

Spotting the problem

The first step is to detect what is malfunctioning. It’s one thing to know there is a leak; it’s another to see where the leak is coming from. This step is essential because if you fix the wrong part, the leak will still exist even if you change it. You will have spent money and time on an unnecessary change.

Problems with the float and the valve

One of the most common problems is that the float is damaged. If the float is too low, it generates a weak water discharge, but if it is too high, the water spills out, and the filling valve does not close.

If the valve does not close, water will be constantly discharged.

To determine if this is the problem, measure about an inch into the overflow pipe and make a small mark. If, when you flush and wait for the tank to fill, the water does not stop at the mark you made, the float is not doing its job.

Chain and flapper problems

The length of the chain may not be correct. This opens the valve by the pressure exerted when it is pulled and causes it to close when it is released. It may not close and have a constant bounce if it does not exert enough pressure.


Another reason could be that the valve is defective and is not sealing the water out when it closes. If the valve does not close with pressure when flushing and releasing the lever, the problem is there.

Fixing Your Leaks

Fixing your toilet is usually not expensive. It’s worse to be charged for the water that is wasted when there is a leak in the toilet. Once you know what part of the flushing system the problem is in, you need to tackle it quickly.

Replacing parts is inexpensive because they are usually sold separately. It’s a matter of buying the replacement, uninstalling the old one, and putting in a new one. What is important is that the part purchased matches your toilet system.

Another option, a little more expensive but still economical, is to buy the whole set of the flushing system and replace it with the old one. This way, you will have everything new and won’t risk fitting a part and having another one damaged by use.