How Much Water Do Running Toilets Use? (Answered)

Written by

Paulk Webb


Freddie J. Hagopian

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how much water do running toilets use

A commode that keeps running can give you noise and cause a high water bill. We know that it might surprise some and ask, “Why? How much water do running toilets use, anyway?”

Approximately 30 to 250 gallons of water a day are wasted (or more) if the toilet stays running, depending on the amount and speed of the leak. Considering that water usage doesn’t only happen in bathrooms, this will reflect on your bill.

Running Toilets: How Many Gallons Per Day Are Wasted?


The average gallons of water a person uses is 40 to 100 a day and 3,000 in a month. Your bathroom is one of the primary consumers and in fact, toilets account for around 30 percent.

In getting the total amount of water usage, you’ll have to include everyone in your home. If you’re a family of four and consume 3,000 gallons of water per month, you’ll have to pay for a total of 12,000 gallons which is $72.93 on average in the United States.

Going back to toilets being big water users, newer commodes follow a standard of 1.6 gallons per flush (gpf), and can even be as low as 1.28 gallons. With this as the basis, a person will use 19 to 24 gallons for daily flushing.

That’s why if you leave your toilet running all day, how many gallons of water will be wasted? It can go from 30 to 250 gallons a day and even more. It’s almost like adding another member to your household and increasing your already expensive bill!

Water Consumption: Running Toilets vs Normal Functioning Toilets


We mentioned that a person using newer commodes with 1.6 or 1.28 gpf spends 19 to 24 gallons daily for 10 to 12 flushes. Multiplied to cover the whole month, it will be 570 to 720 gallons.

If you have older toilets built in the 1980s or 1990s, they operate at 5 to 7 gpf. Suppose you flush the commode 10 times a day, that will consume 50 to 70 gallons. In a month, that’s 1,500 to 2,100 gallons.

But what about a constantly running toilet? For this, we need to look at the following:

  • water used when you flush
  • water wasted when not in use

Since we already know about the first one, let’s take a look at the second through these tables. Note that these are also applicable for other leaks such as a broken faucet, shower, or pipes.

Drips Per Minute Water Wasted/ 1 Month


Water Wasted /1 year


Average Annual Cost for Water and Sewer
10 43 526 $10.91
30 130 1,577 $18.44
60 259 3,153 $36.81
120 518 6,307 $73.59
300 1,296 15,768 $184.12

Suppose you have a slow-leaking toilet that produces 10 drips per minute; you are already wasting 43 gallons a month which can add $10.91 to your annual cost of water. If your leak is strong and has more than a hundred drips per minute, it will add more than $70 to your bill.

The size of the drips also counts since the bigger the drip, the more water is wasted from the running toilet.

For example, you might be curious how much water can a leaky flapper waste. The answer is around 200 gallons per day, which is a whopping 6,000 gallons a month.

Leak Size Gallons Per Day


Gallons Per Month


A-dripping-leak A dripping leak 15 450
A-1_32-inch-leak A 1/32 inch leak 264 7,920
A-1_16-inch-leak A 1/16 inch leak 934 28,300
A-1_8-inch-leak A 1/8 inch leak 3,806 114,200
A-1_4-inch-leak A 1/4 inch leak 15,226 456,800
A-1_2-inch-leak A 1/2 inch leak 60,900 1,827,000

While you don’t have to necessarily measure the size of the leak, the point to be remembered is that a leak wastes water, and this will add to the bill. And the more leak there is present, the more water is wasted, then the bigger addition to the bill.

To summarize, let’s take a look at this comparison table.

Toilet Type Normal Functioning Running Toilet

(broken flapper)

New (10 – 12 flushes per day) 19 to 24 gallons per day 219 to 224 gallons per day
Old (10 flushes per day) 50 to 70 gallons per day 250 to 270 gallons per day

How Much Does It Cost to Leave a Toilet Running?

The cost of running water per hour for toilets will vary depending on the amount of water coming out and the state you’re located. On estimation, a gallon of water costs $0.00295.

Although, it’s possible for running toilets to add around $200 or more to your monthly bill, which translates to $2,400 per year. As we said, it’s like adding another person to your household.

Causes for Running Toilets


We’ve explained how much water we lose with running toilets, but what about what causes the leaks? Below are the most common reasons.

  • Leaky or worn-out flapper. Since the flapper is responsible for letting the water into the bowl, it must open and seal shut when the tank is refilling. If it doesn’t close tightly, water will leak into the bowl continuously.
  • High toilet float. This component determines the water level in the tank, and it should only be an inch below the overflow tube. If it’s positioned too high, too much water will go into the tank and eventually leak.
  • Long and wrongly positioned refill tub This tube connects the fill valve to the overflow tube and brings water to the latter during a flushing mechanism. When the position and length are incorrect, water may continuously run to the bowl even when not flushing.


To explain how much water do running toilets use will depend on the severity of the leak. The possible count is approximately 30 to 250 gallons per day, but it can also be as low as 43 gallons a month.

An example is a broken toilet flapper which can cause 200 gallons of water lost per day. When added to the amount used for flushing, the 19 to 24 gallons per daily flushing of newer toilets will become 219 to 224 gallons, ultimately increasing the water bill.

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