Wales and Northern Ireland: septic tank rules

Wales: register with Natural Resources Wales

NRW says most septic tanks and package treatment plants only need a one-off, free registration. You're eligible if:

• the discharge is domestic sewage only
• the property can't connect to a public foul sewer
• the discharge is far enough from a sensitive site, habitat or species (NRW has a map to check)
• the system meets the required design and manufacturing standards and is suitably located
• it discharges less than 2,000 litres a day to ground through a drainage field, or less than 5,000 litres a day to a watercourse

If the discharge goes to surface water, you must use a package treatment plant. If you can't meet the criteria, you'll need an environmental permit. NRW.

Northern Ireland: NIEA consent to discharge

Under the Water (Northern Ireland) Order 1999, discharging sewage effluent to a waterway or to underground water needs consent from DAERA, through NIEA. For a single home you apply online for a domestic consent, which is granted subject to the local council's Environmental Health (Rivers) Officer's recommendations. NIEA aims to decide within four months, and officers may inspect the site. DAERA.

DAERA also notes that NI Water offers one free desludge a year for domestic septic tanks. DAERA.

Building approval

In both nations, a new or replacement system needs building regulations or building control approval from the council, or in Wales from a registered building control approver.