UK: BSI rainwater guide

The publication of a BSI code of practice represents a significant step forward in the use of rainwater harvesting. This is timely, given the Code for Sustainable homes, and will give guidance to all those involved in applying the technology. A BSI greywater code of practice is also in the pipeline. 

BS 8515:2009 Rainwater Harvesting Systems - Code of Practice gives guidance on the design, installation, testing and maintenance of rainwater harvesting systems for the supply of non-potable water in the UK. It applies to both retrofitting and to new build. It covers systems supplying water for domestic water uses (in residential, commercial, industrial or public premises) that do not require potable water quality, such as laundry, WC flushing and garden watering.

However, it does not cover systems supplying water for drinking, food preparation and cooking, dishwashing and personal hygiene. It deals with individual and communal systems, and those providing stormwater control, but does not cover water butts. A workshop was held at BSI headquarters in February to introduce the code of practice and also to give delegates an update on both rainwater harvesting and greywater reuse. The Chairman of BSI’s Water Reuse Committee, John Griggs, explained how the Standard met Government’s requirements, quoting Defra’s Future Water that said ‘to increase confidence in these developing technologies we will work with others to develop standards for non-potable water use’. To produce such a code was a major organisational exercise and required considerable coordination with other water related BSI committees. BSI Technical Committee CB/506 (Water Reuse) is composed of a wide range of stakeholders including the Environment Agency, DEFRA, CLG, UK Rainwater Harvesting Association, WRAS, Water UK, British Water, Waterwise, CPA, BMA, NHBC, APHC, BPF, BPCF, Loughs Agency, Northern Ireland Environment and Heritage, BRE and various BSI Committee Liaisons. The committee also co-opted Richard Kellagher of HR Wallingford BRE’s John Griggs reminded the audience that this is ‘ not just a committee, we want all the stakeholders to be involved’. 

The code of practice covers three basic types of rainwater harvesting systems: 

•water collected in storage tank(s) and pumped directly to points of use  

•water collected in storage tank(s) and fed by gravity to the points of use  

•water collected in storage tank(s), pumped to an elevated cistern and fed by gravity to the points of use. 

These systems include: 

•internal or external locations for tanks 

• single or multiple linked tanks  

• freestanding or fully/partially buried tanks  

• communal tanks supplying multiple properties  

• packaged systems or components.  

Source: Demand Management Bulletin, Issue 94, April 2009