Register your septic tank or small sewage (package) treatment plant

How to register

If none of the following apply, you will be eligible for a free registration of your private sewage system:

  • your sewage system discharges to surface water and is within 500 metres of a protected or designated area, such as a Site of Special Scientific Interest (SSSI) or Source Protection Zone
  • your sewage system discharges to ground water and is within 50 metres of a protected or designated area, such as a Site of Special Scientific Interest (SSSI) or Source Protection Zone
  • your property has more than 13 people living there and the septic tank discharges to a soakaway in the ground
  • your property has more than 33 people living there and your package sewage treatment plant discharges to a watercourse
  • your sewage discharge is 50 metres or less from a borehole or well
  • your property is within 30 metres of the public foul sewer

We will get in touch following registration if any further action is necessary.

If a building you own is not connected to a mains sewer, your sewage will probably be dealt with by:

  • a septic tank (the liquid soaks through the ground via an infiltration system)
  • a small sewage or package treatment plant (the liquid is treated to a level clean enough to flow into a river or stream)

These facilities must be registered with Natural Resources Wales.

Septic tanks and package treatment plants will in most instances only need a one-off, free registration.

Septic tanks discharging directly to surface water are not permissible and will need to be improved, either by upgrading the treatment system to a small sewage treatment plant or by installing a drainage field and discharging to ground.

Discharging sewage directly to groundwater is not permissible. You must use a drainage field located above the water table.

Cesspits are considered environmentally damaging and should be replaced with a septic tank or private sewage system where possible.

What information do I need to provide?

Have the following information to hand:

  • your name, address and postcode
  • how much water you discharge from your septic tank (estimated by how many people live in your property)
  • if the septic tank or sewage treatment plant is shared with any other property
  • whether the discharge of sewage effluent goes to ground or surface water. If it goes to ground, you can use a septic tank or package treatment plant via a drainage field. If it goes to surface water, you must use a package treatment plant
  • if you are aware of any wells or boreholes within 50 meters (150 feet) of your septic tank or package sewage treatment plant
  • the grid reference for the septic tank or sewage treatment plant discharge. To find out the grid reference go to: (enter postcode, then right click on location of tank)

If you are unable to provide a grid reference or map of the discharge point, we may contact you to help with this after we have received your application.

What happens after I submit my registration?

We will usually process your application within 15 working days.

If your application meets the criteria, we will register your tank/s free of charge.

Does my system meet the required criteria?

Your private sewage system will not meet the required criteria if any of the following apply:

  • your septic tank (soaks to ground through an infiltration system) services 13 or more people
  • your package sewage treatment plant (discharging to a water course) services 33 or more people
  • the sewage system is near a protected or designated area for the environment or a groundwater supply, for example, a Site of Special Scientific Interest (SSSI) or a Source Protection Zone for drinking water (we can check this for you once we have received your application)
  • the sewage discharge is 50 metres or less from a borehole or well

Read about what to do if you have been refused a free registration.

If you need advice about registration please call 0300 065 3000 (Mon-Fri, 9am - 5pm).

After you have registered

Owners of septic tanks and small sewage treatment systems have a responsibility to keep their systems in good order to prevent pollution.

You should:

  • arrange for excess sludge to be regularly removed from the system by a licensed waste carrier
  • make sure that the system is properly maintained in line with the manufacturer's instructions
  • keep all records (maintenance receipts, tank emptying receipts, servicing records) for at least six years
  • tell us if it ceases to operate or you suspect it is causing pollution

If you sell or leave your home, you do not need to tell us. However, any relevant documentation should be passed to the new owner, along with maintenance records for the system. Our downloadable guidance and maintenance log book will help you manage your system effectively and meet legal obligations.

Read more about running and maintaining your septic tank or small sewage treatment plant.

New or existing discharge

If your private sewage system was in place before 6 April 2010 it is classed as an existing discharge. If you have upgraded or replaced your treatment system (or are planning to do so) but still make the discharge to the same place, then this is still an existing discharge.

Registration of an existing discharge is conditional on them being operated and maintained properly in order to avoid pollution.

All discharges made on or after 6 April 2010 are new discharges. If you have an existing system but plan to change or have changed the point of discharge since 6 April 2010, then this should be treated as a new discharge.

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