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Septic tanks

This advice applies to Scotland

This information applies to Scotland only.

On this page you can find out how to register a septic tank, how a septic tank works and what problems can arise with septic tanks.

If you live in a rural area and your home isn't connected to the mains drainage, you're likely to have a septic tank. Its purpose is to treat the waste water from your property and maybe adjoining properties. It's up to you - and your neighbours, if they use the septic tank too - to make sure it works efficiently.

Register of septic tanks

If you use a septic tank, you have to register it with the Scottish Environment Protection Agency (SEPA). You can find out more, including how to register online and what it costs, on the SEPA website. This is a one-off cost.

Registration means that you're allowed to use the septic tank.

If you're unsure whether your septic tank is already registered, you can ask SEPA to check.

If you move into a property with a septic tank, your qualified conveyancer or solicitor is responsible for checking that the tank has been registered. If the details of the property aren't already on the register, they should be added when the property changes hands.

SEPA doesn't hold maintenance records for septic tanks or drainage fields or soakaways. If a buyer wants to know about the condition of a septic tank, they should contact the seller and can request maintenance records. Septic tanks should be emptied on a regular basis, so there should be a record of payment that the service has been carried out.

Building a new home

If you're building a new home, you may decide to use - or have to use - a septic tank because of where you're building.

There's useful information on the SEPA website about what you need to do and what consent is required. You should also have help from an architect, a builder or a planning officer to sort this out.

How does a septic tank work

A septic tank works like a basic sewage treatment works. The waste material settles in the tank and is then digested by natural bacteria. Over time, partly decomposed solids collect at the bottom and form a sludge. This material has to be removed by desludging. If you use a septic tank, you have to make sure that:

  • it's secure and in good working order
  • the drains to and from the septic tank are free flowing and free from blockages.

Your local authority's environmental health department may be able to help if you have problems with your septic tank. It may have a list of local contractors who can maintain and mend septic tanks.

Problems with septic tanks

Shared use

You might have problems agreeing with the people who share the septic tank about:

  • how to maintain the tank, for example the secure lids
  • what to do if it needs to be replaced
  • how to allocate costs for desludging - because properties are different sizes.

You must try to agree about how to maintain your septic tank. Check if there are rules in your title deeds about maintaining the septic tank.

If a repair is required to make the tank safe under the current water regulations and the owners can't agree, one owner can organise the repair by serving a notice on all the owners. The other owners can appeal against the notice. All the owners will be responsible for sharing the costs of the repair and any legal costs.

If you fail to check the tank properly and there's a leak because of poor maintenance, you could have a statutory notice issued to force you to maintain, repair or improve the tank. You can read more about resolving neighbour problems.

Septic tank blockages and overflows

If you're the person who uses the tank

The people who use a septic tank are responsible for any blockages or overflows. If you don't fix the problem and there's some discharge, you're causing pollution. The Scottish Environmental Protection Agency, your local council or your neighbours could take steps to force you to sort out the problem. 

If you want to report a leaking septic tank

If a neighbour’s septic tank is leaking and causing problems, your options will depend on what effect the leak is having.

If the tank is leaking into nearby streams or rivers and causing pollution, then you can contact the Scottish Environmental Protection Agency (SEPA). SEPA will contact the users of the septic tank to discuss the problem and to try to help them resolve it informally. If this isn’t possible, SEPA can serve notices on the owners requiring them to take steps to stop the pollution. Find your local SEPA office

If the tank is causing problems on land such as creating a damp patch of ground that has an offensive smell or affecting your neighbour’s water supply, then you can contact the Environmental Health Department of your local council. The problem could be a statutory nuisance. Councils have powers to serve notices, requiring owners to carry out works to stop the problem. If owners don’t do the work then they could be committing a criminal offence. Find contact details for your local council.

If your local authority won't take steps against the owner of the septic tank, you could take civil legal action against the owner yourself. You should get legal advice. Read about getting help with a legal case.

Supply of a septic tank

Septic tanks range in price from several hundred to several thousand pounds. You should contact your local authority's environmental health department, as they may have information about local stockists. A local firm may have a maintenance contract that you can also draw up at the time of purchase. If this is in writing, it will be evidence of the contract, although a verbal agreement may be enough to have a contract.

Desludging a septic tank

You can choose to use the desludging service provided by Scottish Water or by a private firm. If you choose the services of a private firm, you should make a contract with them.

Scottish Water's desludging service

You can choose between:

  • a scheduled service - this is a planned service with desludging at regular intervals and you'll be asked to sign a contract for this service
  • an unscheduled service - if you give Scottish Water at least five days' notice, they can call to desludge at your request. This service is more expensive than the scheduled service.

If you have a serious problem that needs immediate attention, there's an emergency service called an urgent response service. Scottish Water will try to provide the service within two working days. This is the most expensive service for desludging.

Charges for desludging

If you use Scottish Water to desludge your septic tank, their charges are based on standard sizes and reasonable access to the septic tank. If your tank doesn't match the specifications and conditions for the standard charges, Scottish Water may still be able to desludge the tank but will quote a price for your tank.

To arrange desludging, contact Scottish Water's customer helpline on 08000 778778.

You'll get a bill within 30 days for any desludging. If you don't pay it, Scottish Water will refuse to come back to your septic tank to desludge it on another occasion.

You can check the current charges for desludging on the Scottish Water website.

Paying for sewerage services

You don't have to pay for sewerage services from the local authority on your council tax bill. The septic tank should provide all the sewerage service that you need.

More information

There's more information about septic tanks on the Scottish Water website.

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