Water Efficiency Calculations

Part G Building Regulations changed on 6th April 2010 and all new homes and conversions are now required to meet new water efficiency targets.

This means that Building Control will now be asking for calculations to show that no more than 125 litres of potable water per person, per day are used in all new houses and conversions. In practice this means that developers will now have to consider what types of taps, showers, WC’s, baths and other appliances they will be fitting.

We are very experienced in potable water calculations and there are two main routes for developers to take. Firstly rainwater harvesting systems can be installed to capture rainwater and reuse it in WCs, washing machines and outside taps. These systems can have a very significant effect on reducing potable water consumptions to under the maximum 125 l/p/d. Alternatively reduced flow taps & showers, more efficient WC’s, dishwashers & washing machines and sometimes smaller baths will need to be installed.

We can provide the formal calculations now required by Building Control as well as guidance on what types of taps, showers etc. will need to be fitted. We would recommend these are done early in the build process to ensure the proposed fittings will meet these new requirements.

Please call us for further advice.

To download our guide to Water Efficiency please click here.


“I found MES as our development company needed building regulation compliance certificates for our built units. From the moment contact was initiated they were the consummate professionals. Friendly, courteous, knowledgeable and very prompt on providing the information our company relied upon. I would recommend MES in a heartbeat”

Lorna Bucknall
Visual Development Ltd


By continuing to use the site, you agree to the use of cookies. more information

The cookie settings on this website are set to "allow cookies" to give you the best browsing experience possible. If you continue to use this website without changing your cookie settings or you click "Accept" below then you are consenting to this.