Septic tanks and other domestic waste water treatment systems


Domestic waste water treatment systems, such as septic tanks, collect, treat and discharge waste water from households that are not connected to public sewer systems.

If you have one of these systems, you must register it. It can be inspected by a local authority to prevent any risk to the public and the environment.

Do I have to register my septic tank?

All domestic waste water treatment systems, including septic tanks, must be registered with your local authority. There is a fee of €50 to register your waste water treatment system.

You can register and pay online at

If you do not register your system and are convicted, you could be fined up to €5,000.

If you want to get a grant to repair or replace your treatment system in the future, your treatment system must be registered within a certain time frame. Replacement systems do not need to be re-registered.

Will my treatment system be inspected?

Your waste water treatment system can be inspected by the local authority. Your local authority will write to you and let you know that they will be inspecting your system. They will give you at least 10 working days’ notice before the inspection.

If your waste water system is going to be inspected, you should:

  • Have your waste water systems registration certificate
  • Know where your waste water treatment system is
  • Have any paperwork about your system’s installation or maintenance

Inspectors are appointed by the Environmental Protection Agency (EPA) and must show you their identification if you ask for it.

If your treatment system is working properly, you will get a certificate that confirms this. If the inspector finds issues with your system, you will get an advisory notice within 21 days of the inspection. This notice will outline the problems with your system and give you a certain amount of time to fix them. You may be able to get a grant to repair or upgrade your system (see below).

Find out more about maintaining your septic tank and septic tank inspections.

Can I get a grant to repair or replace my septic tank?

You may be able to get a grant to repair, upgrade or replace your waste water treatment system. You can apply for funding for 85% of the cost of the repairs to your system or a new system, up to a maximum of €12,000.

On 1 January 2024, the septic tank grant was updated. The grant increased from €5,000 to €12,000 and the qualification criteria changed so people could get the grant even if they hadn’t registered their septic tank by 1 February 2013.

For more information on how to apply, see below.

Different types of grants

There are 3 different waste water treatment grant schemes. One grant (pdf) is available for people to upgrade or repair their system following an inspection. While the other 2 grants are only available if you live in a particular area, and are notified by your local authority that you are eligible to apply.

Find out more about the criteria for each of the schemes on

You cannot get a grant for the routine maintenance, servicing or de-sludging of a treatment system.

How to apply for a septic tank grant

Application forms for each scheme are available from your local authority.

For more information on these schemes, you can contact the rural water section of your local authority.

More information on septic tanks

The Environmental Protection Agency has published a set of Frequently Asked Questions about waste water treatment systems.

There is also a detailed set of FAQs on

You can contact your local authority or the Environmental Protection Agency for more information.

Page edited: 15 May 2024