It’s time to upgrade

Revised regulations in England for septic tanks discharging to watercourses will be introduced in 2020. Andrew Baird of wastewater specialist WPL explains how this will affect self-builders with onsite treatment, and when they will need to upgrade


omeowners using off-mains treatment prefer to think about it as little as possible, but with Environment Agency rules about to change, it may be time to give yours some attention.

Unlike other parts of the UK, homeowners in England with private sewage treatment do not require a licence or registration provided that they are not discharging to an area of outstanding natural beauty or directly to groundwater where domestic and commercial abstraction is being undertaken. However, those whose facilities are found to be polluting the land or water do still risk prosecution. The situation in Scotland is different, as householders need to purchase a Controlled Activity Regulations (CAR) licence to discharge anything to land or water. In Wales, onsite sewage treatment systems need to be registered with Natural Resources Wales and in Northern Ireland the discharge of domestic sewage to any surface water or groundwater requires the consent of the NI Department of Environment.


Traditional septic tanks pose a high pollution risk due to low-grade treatment within the tank and the poor quality of the wastewater discharged. Many are ‘legacy systems’ from a time before dishwashers and washing machines, when domestic water use was lower and are not suited to modern consumption. The updated Environment Agency rules means that householders in England with a septic tank discharging to a watercourse now have until 1 January 2020 to carry out an upgrade. If they want to sell an affected property before this date the upgrade must happen first. If the Environment Agency finds evidence that a septic tank discharging to surface water is causing pollution, it will need to be replaced or upgraded prior to 2020. Usually this has to take place within a year, although it tends to be agreed on a case-by-case basis.


A newly installed discreet sewage treatment plant at a country cottage

Domestic sewage treatment plants have improved massively over the last decade

According to the Environment Agency, the options available to householders needing to upgrade are: • Connect to mains sewer where available

• Install a drainage field so the septic tank can discharge to ground instead of water

• Replace your septic tank with a small sewage treatment plant


Domestic sewage treatment plants have improved massively over the last decade and much more robust systems are now available. There are packaged treatment plants on the market that meet all the requirements of the new rules and incorporate an aerated process designed

to handle the increased flows associated with contemporary lifestyles.

Sizing is very important when selecting any domestic sewage treatment system and ideally householders are advised to select a supplier accredited by the industry trade association British Water. They should ask their supplier to demonstrate that the system they are recommending complies with British Water’s Flows & Loads code of practice for package treatment plants. To deal with our water-intensive contemporary lifestyles, the

recommendation is for 150 l/d per person throughput. Less scrupulous suppliers may recommend smaller plants to cut costs, but upsizing at a later date will incur additional expense down the line

january/february 2018

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