Water and Drainage

Supply

To reduce water consumption, bathroom and/or kitchen fixtures and fittings to modern equivalent should be upgraded, including:

• Spray taps
• Low flow rate showers (<9 litres/min)
• Low cistern volume WCs
• Economic dishwashers / washing machines

Drainage

• Connect to municipal sewage system for foul drainage, if possible;
• If there is no available public drainage system, a septic tank would be the next consideration;
• Solutions such as composting toilets and reed beds are ideal in environmental terms, however, would require maintenance and upkeep by the users.  This is generally an unpleasant and undesirable task, and should only be considered in situations where conventional sewage solutions are unavailable, and where the client has requested it and has a full understanding of what will be involved;
• Consider Sustainable Drainage Systems for external drainage – soakaways, swales, ponds, porous paving, etc; and
• Reduce volume of external surface water drainage for example through arrangement of landscaping, consideration of green roofs.

It must be pointed out that whilst passive treatment systems, such as reed beds and compost toilets, require less maintenance than those systems with mechanical parts, all sewage treatment systems require some maintenance and upkeep; packaged sewage treatment works require regular servicing, and septic tanks and cesspools require emptying (with the frequency being dependent on use).

Grey water

Sustainable drainage techniques should be utilised for surface water disposal and should follow the principles of the ‘Surface Water Management Train’ so that runoff from development sites is controlled and mimics Greenfield runoff whilst maintaining natural drainage patterns as far as possible.

• Consideration of rainwater harvesting for applications including flushing of WCs and irrigation;
• Grey water collection from sinks, basins, baths, etc, and re-use is the less favoured option, and is likely to be appropriate for only a small minority of projects.

Techniques including green roofs, soakaways, swales, porous pavements, ponds can all be utilised.