All new homes are required to have CSH rating (since May 2008).
Aquaflow addresses the surface water run-off category and water quality
Site discharge must be at pre-development run-off rates up to a 100 year return period including climate change. This is if;
Post development run-off volume is no greater than pre-development including climate change
or
Restricted to Qbar up to an 100 year return period
An amendment to the CSH has recently intergraded the importance of water quality into the assessment process. Aquaflow meets and in may cases exceeds these standards.
Additional credits for the code
2 credits are available for using SUDS to improve water quality.
In June 2007 the Hanson EcoHouse at BRE Watford had a real CSH assessment. Aquaflow provided 4 credits for surface water drainage and flood risk. It also was given 5 credits for internal and external water usage. The assessment was conducted by Arups. The EcoHouse was the first masonry house to undergo assessment the UK. The EcoHouse received a code 4 status.