# How do I calculate my monthly water usage?

In terms of water usage, how much is 10 cubic meters of water?

I ask this because I live in a small apartment with another person and our monthly water bill is now over 6 times higher. When I called the water company, they tell me that they give me 10 cubic meters of water per month, and during the last bill we used 29 cubic meters of water (almost triple the allowed use).

Nothing in our water usage has changed, so I guess my question is how much is 10 cubic meters of water in terms of showering, doing laundry, etc?

In our case, we both take two showers per day and we do laundry once (sometimes twice) per week. But nothing else has changed.

• you might have a leak somewhere. can you see the water meter's reading? if so, turn everything off and see if it's still going. if so, you need to call your landlord. – dandavis Mar 13 '19 at 17:29

1 cubic meter is 1,000 liters of water. 1,000 liters is about 264 gallons. You are allotted 10 cubic meters or 2,640 gallons, which is quite a lot.

The Average American Shower is about 17 gallons. 4 showers per day times 31 days is 2,108 gallons of water. Your worst case scenario for Washing Machine Water Usage is about 25 gallons, at 6 times per month that would be 150 gallons. Also, consider that a toilet flush is about 2 gallons. If you flush twice per day that's another 125 gallons of water. You can figure about that much for typical hand washing, etc. At this point you are at about 2,500 gallons (9,463 liters). That's roughly about what you are allowed to use.

• Do you have a separate water meter? If so, record the reading. Take another reading the next month and get the difference, multiply by what the meter calls for to determine your usage.
• Turn all of the water off in your apartment and go see if the meter is spinning. If so, you have a leak somewhere.
• Check to make sure the toilet flapper is not allowing water to run after you flush. This will make the toilet keep trying to fill.
• Do you have any water dripping at faucets or underneath the sinks?
• Change the aerators in your shower and sinks.

Anything you can do to reduce your water consumption will ultimately lower your bill.

• I wish the US would change to the metric system, but it seems it won't happen anytime soon. The OP is reporting water use in m^3 suggesting that she may be in the UK or Commonwealth (including Canada) in which case the relevant gallons are different from galUS. 1 galUK = 1 galC = 1.20 galUS, and 10 m^3 = 2200 galUK = 2640 galUS. – Jim Stewart Mar 13 '19 at 17:06

I'm going to have to put this in terms I understand, but 10 cubic meters of water (is that really what the water company quotes you?) is 2,600 gallons or 10,000 liters.

Lets say a shower takes 10 minutes, and uses about 2.5 gallons per minute (assuming a low-flow shower head). That's 25 gallons per shower. Laundry is going to be around the same amount depending on the machine used. You're going to wash hands and flush toilets, so there's more water on top of what you stated. So, your usage doesn't seem to add up to that much.

However, one leaky toilet can use a lot of water quickly. If the flush valve sticks open, the water is going to run at around 2 gallons per minute. If that happens all night (8 hours) that would be 8 * 60 * 2 = ~1000 gallons of water in just one night!

Unexpected water usage is often because of leaky toilets or faucets. Irrigation is another major offender, but not in an apartment.

10 cubic metres is 10,000 litres.

If your shower uses 20l/min and you have a 5 minute shower that is 100 litres. So, for 4 showers that is 400 litres per day.

If, however your showers are 15 or 20 minutes then at 20 minutes * 20l/min that is 4000 litres...

Then factor in if you have the tap running when you clean your teeth, you sink water use for shaving etc...

And how many times you use the toilet and flush per day each - does the toilet have a dual-flush or not - that can also make a big difference...

The only way to estimate is to record your detailed activity and the volume flow for each item and work out what is happening...