It is easy to look at environmental impact and just focus on renewable energy and carbon reduction, but it is equally important to remember water efficiency. Recent press has highlighted the terrible effects the fashion industry has had in polluting water courses and drying up vast expanses of water from lakes to reservoirs. We have also seen the tragic effects of climate change on weather in places, close to home, such as the devastating rainfall in Spain.
In the UK we do tend to take drinking water for granted, but with greater demand on water supplies through increases in the population, new housing and changing weather patterns it is a useful time to remind ourselves of the Building Regulations Approved Document G in England and Wales and Water Efficiency.
Both approved documents for Wales and England state that wholesome water supply and consumption must not exceed 125 litres per person per day. This includes water for sanitary appliances along with white goods and a fixed allowance of 5 litres per person per day for outside use. In England, an ‘Optional Requirement’ may be applied to a project, this would be identified during the planning stage of the new property and listed within the requirements of the planning permission.
Where the ‘optional requirement’ is applied, the water consumption must not exceed 110 litres per person per day.
How do we calculate the water demand to ensure compliance with building regulations?
In England the most straight forward way is to use the prescribed fittings approach as an alternative to calculating the water consumption. Where the fittings approach is used, the water consumption of the fittings provided must not exceed the values in the table shown. If they do, the water efficiency calculator must be completed to demonstrate compliance.
In addition, if a shower is not to be provided or where a waste disposal unit, a water softener or water re-use is to be provided, the water efficiency calculator must be completed.
| Maximum fittings consumption | |||
| Less than 125 litres/person/day using fittings approach | Less than 110 litres/person/day using fittings approach | ||
| Water fitting | Maximum consumption | Water fitting | Maximum consumption |
| WC | 6/4 litres dual flush or | WC | 4/2.6 litres dual flush |
| WC | 4.5 litres single flush | WC | – |
| Shower | 10 l/min | Shower | 8 l/min |
| Bath | 185 litres | Bath | 170 litres |
| Basin taps | 6 l/min | Basin taps | 5 l/min |
| Sink taps | 8 l/min | Sink taps | 6 l/min |
| Dishwasher | 1.25 l/place setting | Dishwasher | 1.25 l/place setting |
| Washing machine | 8.17 l/kilogram | Washing machine | 8.17 l/kilogram |
The Welsh Approved Document specifies use of the Water Efficiency Calculator for New Dwellings, published in September 2009 by the Department for Levelling Up, Housing & Communities. This is the same calculator specified in the English Approved Document but is no longer available as a separate publication. The Approved Document G for England has an online calculator, alternatively there are several online versions available from third parties including manufacturers.
New wholesome and non-wholesome supplies to a dwelling are notifiable to the local building control body. This may well be part of the whole-building, building control submission, but it is always best to check the contract conditions. If it is not included, or separate notification is required then this can be done directly with building control for a fee, alternatively you can self-certify the installation through membership of a Competent Person Scheme.
In addition to building control notification, separate notification will have to be made to the local water undertaker in accordance with the Water Supply (Water Fittings) Regulations 1999.
Finally, improved water efficiency benefits everyone and should not just be applied because regulations say we must. Charities like Water Wise, (www.waterwise.org.uk) or your customer’s local water undertaker will have lots of free advice for consumers and some provide discounted or free water saving products.