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How to Measure Your Flow Rate

Calculating Flow Rate

To choose to a filter system with the correct capacity for your home it is important to know how to measure your flow rate. In order to serve as a rough guide for choosing your water filter and treatment system, the table below shows average flow rates in Litres per Minute (LPM). Please note these are average flow rates and not maximum flow rates, so see the section below for guidance in working out your maximum water flow rate.

Average Flow Rates

How to find out the flow rate of your water

In order to buy the correct Ultra Violet UV system for example, it is important to have an approximate estimate of your water flow rate. Your water flow rate is simply the amount or bulk of water which moves through your pipes over a minute or hour.

The simplest way to get a reasonably accurate measure of your water flow rate is to time yourself filling up a bucket. So for example if you fill up a 10 litre bucket in 1.5 minutes, then your flow rate will be:

10/1.5 = 6.66 Litres per minute.

Don’t get confused between flow rate and pressure. Flow Rate is the amount of water that any given system will pass over a specified period of time. Pressure is the standing pressure of the system under no-flow conditions. It is important to know about the maximum amount of water you use at any one time. Your water will only flow when you turn on your taps, so the number of taps you have on at any one time will obviously affect your flow rate.

If you need any further help or advice about selecting a Ultra Violet (UV) Water Treatment or other system, please call us on 020-3507-1879 or fill out the contact us form.

If you know your flow rate, browse our range of UV systems.

Calculating your maximum flow rate

This can be very tricky and even the best plumber will still be guessing. The very best way is to install a water meter at the source and this will tell you exactly how much water is flowing per minute. If you check this at different times of the day, especially at times when you think the most amount of water is being used (i.e. first thing in the morning when everyone has a bath or shower, flushes the toilet and so on), then this will give you the best indication of the peak amounts of water use and the amount of litres per minute your household consumes.

Learn more about Flow Rate

If your are interested to learn more about flow-rate and fluid dynamics, watch this lecture:


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