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Water Usage Calculations

Water Usage Calculations for Residential Developments

Under Part G of the Building Regulations, water usage calculations are a requirement for new residential developments, conversions, and some extensions.

It specifies that dwellings must have a projected consumption of no more than 125 litres of water per person, per day.

We can help you reach acceptable levels of water usage in your building. We have been in the industry since 2010 and have helped many residential developments meet government standards.

Book a consultation today.

new build development

How are Water Efficiency calculations worked out ?

propcert engineer

The government uses its water efficiency calculator for new dwellings methodology for evaluating residential projects. This is in support of The Code for Sustainable Homes and the Building Regulations. We use the same methodology in calculating water usage in your project.

The results will be in litres per person, per day. Once done, we will give you a copy of the computations which you can use to adhere to regulation. If your development doesn’t get a pass the first try, we will also give you adjustment recommendations to make your fittings more efficient and help you pass your next calculation.

What is assessed ?

Some of the considerations when calculating the water usage of a residential development are:

  • The rate of water flow in taps and showers
  • Bath capacity
  • Dishwasher consumption
  • The flushing capacity of water closets
  • The use of on-site greywater or rainwater harvesting
  • The use of washing machines per kg of dry load
  • More than the government mandate, assuring water efficiency increases the sustainability qualities of your property. Increasing number of buyers and renters are considering this, too.
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Why PropCert?

Since 2010, we have been providing you with EPCs, EICRs, CP12s and lots more. We’ll take the stress out of getting certified, keep you compliant and your tenants safe. 

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