Can't find your answer? Read our regulations guide and cost guides, or send us an enquiry and a local installer can advise.
Frequently asked questions
Are you an installer?
No. We're a free matching service. We pass your enquiry to up to 3 independent installers who cover your area, and they contact you to arrange a visit and quote. We don't carry out any work ourselves.
Is the service free?
Yes, it's free for homeowners. We may receive a fee from installers for introductions. There's no obligation to accept any quote.
How many installers will contact me?
Up to 3, depending on who covers your area and is available. Sometimes there may be fewer in remote areas.
What's the difference between a septic tank and a sewage treatment plant?
A septic tank settles out solids, and the liquid then needs a drainage field to finish the treatment in the soil. A treatment plant uses powered parts to treat wastewater to a much higher standard, so it can often discharge to a watercourse.
How much does a new septic tank cost?
The tank alone is about £1,200 inc VAT for a 5–6 person unit from merchants. Installers publish roughly £3,000–£7,000 for a like-for-like replacement, from about £5,500, and commonly £5,000–£15,000, for a new tank with a drainage field, and more on difficult sites. See our cost guides for sources.
How much does a sewage treatment plant cost?
6–7 person units cost about £2,190–£2,700 inc VAT from merchants (equipment only), or about £4,950 for a Klargester BioDisc. Supplied and installed, installers commonly quote £7,500–£15,000.
Do I need permission for a new septic tank?
Yes. You need building regulations approval (a building warrant in Scotland) and the right environmental authorisation for your nation: the general binding rules or a permit in England, SEPA in Scotland, NRW in Wales, or NIEA in Northern Ireland.
My septic tank discharges to a ditch. Is that a problem?
In England and Wales, yes. Septic tanks must not discharge to surface water, so you'll need a treatment plant, a drainage field or a mains connection. In Scotland and Northern Ireland the regulator sets the conditions for your discharge.
How often should a septic tank be emptied?
Usually at least once a year, or as the manufacturer recommends. Always use a registered waste carrier.
What happens to my details?
We only use them to handle your enquiry and share them with up to 3 relevant local installers. See our privacy policy for full details and your rights.