Building in the Countryside: Drainage and Water

ABOVE: Installing a bio-digester sewage treatment plant (read more below).

Drainage should be a high priority when assessing a rural plot, and if it’s not evident you’d be wise to make enquiries as to whether provisions are already in place. If not, a solution needs to be sought from the outset, with plans for drainage provision submitted with your planning application.

Local authorities encourage mains connection if your new home is within 30m (100ft) of a public drain — the standard connection charge is £245 in England and Wales. However, both gravity and distance can work against you on rural plots. It’s worth exploring your options to pump sewage – using a package pump system – to the mains first. You’ll need expert help to calculate the right system for your site. Things become more complex when the location of the nearest drain will mean the highway needs to be dug up to make a connection — the costs of which can be excessive and can outweigh off mains (SEE BELOW).

Clean water is a necessity for any new house, but connection will depend on your location. In England and Wales mains connection is via the local water board and, as such, costs vary considerably. In Scotland and Northern Ireland, however, publicly owned water companies mean standardised charges. Scottish Water’s connection fee is £302.70, but you’ll also be subject to an infrastructure charge of £288.50 (scottishwater.co.uk). With Northern Ireland Water standard connection is £216 with an infrastructure charge of £263 (niwater.com). As with drainage connections, you’ll also have to factor in additional funds for excavation, pipes etc.*

Around 25,000 UK homes are not connected to mains water, according to DEFRA. Alternatives include sourcing water from springs and wells or installing a borehole. The capital costs associated with these off-mains options are high, but if you intend to live in the property for the foreseeable future, then you’ll benefit from low running costs. To install a borehole you’ll first need a survey from the British Geological Survey, costing £352 incl VAT. This will “provide a rating as to how cost-effective a borehole would be,” states Mark Jenning of Synergy Boreholes (synergyboreholes.co.uk). Installation costs between £5,000-16,000, but factor in an additional £3,000 for equipment for drinking water — which will require regular inspection.

Consent to Discharge

If there’s a watercourse nearby you may be able to discharge treated effluent, but you must first obtain a Consent to Discharge. In England and Wales this is granted by the Environment Agency (0870 850 6506) — the application charge is £124. In Northern Ireland, through the Department of Agriculture and Rural Development’s Rivers Agency (riversagencyni.gov.uk), the application charge is £110. In Scotland the online fee is £76 with the Scottish Environment Protection Agency (sepa.org.uk).

"It truly was primitive"

John Hughes and Harriet Wilson’s isolated plot in Exmoor National Park was originally home to a derelict wooden chalet with no mains services. “The old chap sourced his drinking water from the stream,” says Harriet. “It truly was primitive.” Water for their new home (BELOW) is now provided via a borehole, and supplemented by a rainwater harvesting system. The home also boasts a bio-digester sewage treatment plant (on site MAIN IMAGE) — “Which is ideal as we didn’t require a Consent to Discharge for it,” Harriet comments.

The family decided against oil and LPG — PV cells and a ground-source heat pump provide hot water and heating for the house. “If you’re building a new house, it’s worth putting in renewables from the start: they pay for themselves almost immediately,” advises Harriet.

Off-Mains Drainage Solutions

Septic Tanks: This unit (BELOW) separates solids – which are slowly broken down – from liquids (effluent) which are discharged, then filtered via a soakaway or drainage field. The tank provides limited treatment – containing around 70% of the waste which first entered it – meaning annual ‘desludging’ will be required (at about £75 a time).

The capital costs are high. A 3,800-litre tank together with a 45m soakaway – suitable for a household of four – will cost £5,200 to purchase and install, according to Kingspan Environmental (kingspan.com).

The tank and drainage field will need to be located a minimum distance from both the house and any nearby water courses. A trial hole and percolation test will also need to be carried out first to assess whether your site is suitable — areas with heavy clay soils, a high water table or bedrock are often not. You may also require a Consent to Discharge (SEE ABOVE).

Cesspools: Cesspools only collect waste and as such require frequent emptying – around £50-80 each visit – meaning running costs are high. They’re even banned under Scottish Building Regulations.

Treatment Plants: Package sewage treatment plants provide superior results, as Mike Norton, Technical Director of Kingspan Environ - mental, states: “If you want to be safe and, frankly, more environmentally friendly, install a sewage treatment plant — which will remove 90-95% of sewage pollutants without relying on a soakaway to do half the job.” They cost approx £5,700 to buy and install.

Some models are powered by electricity – increasing the cost of utility bills – though models which harness wind and solar power are also available.

You’ll also need to consider the cost of regular servicing, as well as desludging, meaning they’re more expensive to run than septic tanks. But remember that while septic tanks may provide the cheaper and easier solution, they are not necessarily the best option.

Reed Beds: Reed beds provide an eco alternative for treating effluent — and may be a prerequisite for a Consent to Discharge. The horizontal reed bed is currently the most common, but you’ll require a considerable area to accommodate one. The vertical flow reed bed requires less space, but you’ll need to dig down deeper to enable waste to filter through.

The capital costs – upwards of £15,000 – are high. Weeding and maintenance will also be required to ensure the reeds remain the dominant species.

Rainwater Harvesting: Whether you rely on mains or an off-mains alternative for water, it is well worth investing in rainwater harvesting — which can reduce your reliance on your principal source by up to 50%. Rainwater harvesting ranges from the simple rain butt for garden use, to sophisticated systems which collect, cleanse, store and pump water into the home for use in appliances.

Systems are becoming more affordable and, according to Adrian Lester, Partner and General Manger of rainwaterharvesting.co.uk, “The prices have come down for the bigger kits — from £4,000 to more like £2,500. For a small house, £1,500 will enable you to flush the toilet and wash your clothes with water off your own roof.” Adrian also recommends that “the best time to install rainwater harvesting is at build stage when the earthmovers are already on site”.

How to self build in the countryside:

• How to Self Build or Renovate in the Countryside
• Planning Permission
• Fuel and Energy

Further reading:

• A Guide to Plumbing and Heating for Your Self Build
• Off Mains Drainage Solutions