HOW TO HIRE · PLUMBING & HEATING

How to hire a septic tank installer in the UK
The checks, the questions and the paperwork.

No register applies, but a new septic system needs building regulations approval and must meet England's general binding rules.

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THE 60-SECOND VERSION

Hiring a septic tank installer in five steps

  1. Ground or surface water?A septic tank must discharge to ground through a drainage field; to a stream needs a treatment plant.
  2. Building regulations approvalAgree who applies and get the reference before digging.
  3. Check if a permit is neededSome discharges need an environmental permit; check before choosing the system.
  4. Percolation testThe ground is tested to design the drainage field.
  5. British StandardNew systems should meet the current British Standards.

BEFORE YOU BOOK

Check before you book

No register applies

No licence or register applies to septic tank installers in any UK nation; what is regulated is the system and the building work.

Ask the installer for a written design and who will apply for approvals.

Building regulations approval

gov.uk's general binding rules guidance says you must have the appropriate building regulations approval for a new treatment system, and may also need planning permission. In Scotland a building warrant applies; in Northern Ireland council building control.

Get the building control reference for the septic tank installation before work starts. gov.uk →

General binding rules and permits

Under the Environment Agency's general binding rules for England, a new septic tank must discharge to ground through a drainage field, never to a watercourse, and the system must meet the current British Standards. Discharges outside the rules need an environmental permit.

Ask the installer which rules the design meets and whether a permit is needed. gov.uk →

Waste from the old tank

Sludge from an old tank must go to a registered waste carrier, and under section 34 of the Environmental Protection Act 1990 you must pass waste only to an authorised person.

If an old tank is being emptied or removed, check the carrier's registration. gov.uk →

VAT

Installing a septic tank or treatment plant is standard-rated at 20%, digging and drainage field included. Over the £90,000 registration threshold a trader must charge it and show it separately; under it there is no VAT and no VAT number.

Ask the septic tank installer for its VAT number and whether the price includes VAT. gov.uk →

“Septic tank or treatment plant — which does my site need?”

A good answer: A reasoned answer from where it discharges; a stream means a treatment plant.

“Who applies for building regulations approval for the septic tank?”

A good answer: A named person and a reference before digging.

“Does this septic tank installation need an environmental permit?”

A good answer: A check against the general binding rules.

“Will you do a percolation test?”

A good answer: Yes, to size the drainage field.

“Does the tank meet the current British Standard?”

A good answer: Yes, named.

“What happens to the old tank?”

A good answer: Emptied by a registered carrier and removed or filled, priced.

Getting the quote right

  • Tank or plant model and size
  • Drainage field design and length
  • Building regulations fees and permit, if any
  • Excavation, backfill and reinstatement
  • Old tank removal
  • Who actually attends to dig and install — the installer's own crew or subcontracted groundworkers
  • The VAT number, and VAT at 20% as its own line

Walk away if

  • Plans a septic tank discharging to a stream
  • No building regulations approval
  • No percolation test
  • No mention of the British Standard
LOW
£2,500
TYPICAL
£5,500
HIGH
£12,000

What a septic tank installer costs: £2,500–£12,000 per install

Septic tank installations are priced per install after a survey; the drainage field and ground conditions set much of it. Septic Tank Installation price guide →

Guide prices compiled by the Locufy team from published Irish and UK provider price lists and 2026/27 cost guides. Updated 2026.

KNOW WHAT TO LOOK FOR? NOW FIND ONE

Septic tank installers near you, with the badges that matter shown

ID checked, trader status and one score from every review — on the card, before you message anyone. Nearest first. No account needed to look.

Or post the job free and let them come to you.

  1. Survey and testPercolation test and design.
  2. ApprovalsBuilding regulations approval and any permit.
  3. ExcavateTank hole and drainage field trenches.
  4. InstallTank set level, connected and backfilled; drainage field laid.
  5. Sign offBuilding control inspection and handover.

Percolation test
Measures how fast the ground drains water.
Drainage field
Perforated pipes that disperse treated water into the ground.
Treatment plant
A powered system cleaning sewage to a higher standard.
Environmental permit
Permission for a discharge outside the general binding rules.
BS EN 12566
The current standard for septic tanks and small treatment plants.
Backfill
Filling round the tank after installation.

AFTER

When the job is done

Keep the completion paperworkBuilding control sign-off and the tank's British Standard documents.
Keep the maintenance instructionsEmptying frequency and servicing.
Tell a future buyerIn England the seller must give written notice of the system and its maintenance.
Leave the reviewReviews on Locufy are tied to a booking, so yours about the septic tank installation carries weight. If something is not right, the make-it-right step gives the septic tank installer the first chance to fix it before it is published.

STEP 1Complain to the septic tank installer firstWrite it down: what the septic tank installer did, what is wrong with the septic tank installation and what would fix it. Reasonable care and skill is the standard section 49 of the 2015 Act sets; if the septic tank installation missed it, ask for the work to be redone free, or for part of the price back.
STEP 2Use the make-it-right stepGive the septic tank installation fewer than four stars and you can send the issue to the septic tank installer first; we stay on it until there is an answer, and then your review is posted.
STEP 3Building control and the regulatorUnapproved work is a matter for council building control. Pollution from a discharge goes to the Environment Agency in England, Natural Resources Wales, SEPA or DAERA. For a dispute, Citizens Advice (0808 223 1133), Advice Direct Scotland (0808 800 9060) or Consumerline (0300 123 6262).
STEP 4Small claims, if money is owedA claim against the septic tank installer that will not settle can go to court without a lawyer — the small claims track for up to £10,000 in England and Wales, simple procedure for up to £5,000 in Scotland, and the small claims court for up to £5,000 in Northern Ireland.

Hiring a septic tank installer: questions people ask

Yes. gov.uk's guidance says a new treatment system needs building regulations approval, and possibly planning permission.

Not if the discharge meets England's general binding rules; otherwise an environmental permit is needed.

Not in England; a discharge to surface water needs a treatment plant.

£2,500–£12,000 per install, around £5,500 typical. The septic tank installation price guide has the detail; enter your town above for installers near you.

In England the seller must give the buyer written notice of the system and its maintenance needs.

Two to seven days on site.

MORE GUIDES

More hiring guides in plumbing & heating

How to hire: Septic Tank EmptyingHow to hire: Septic Tank Inspection & RepairHow to hire: Drain RepairHow to hire: CCTV Drain SurveyHow to hire: Drain UnblockingHow to hire: Sump Pump InstallationHow to hire: PlumberHow to hire: Pipework InstallationAll 701 hiring guides →

Septic tank installers near you

Septic tank installers in LondonSeptic tank installers in ManchesterSeptic tank installers in BirminghamSeptic tank installers in GlasgowSeptic tank installers in BelfastAll septic tank installers on Locufy →

Sources — checked October 2026

  1. gov.uk — general binding rules: small sewage discharge to the ground (England)
  2. gov.uk — general binding rules: small sewage discharge to a surface water (England)
  3. gov.uk — septic tanks and sewage treatment plants: what you need to do
  4. gov.uk — building regulations approval (England)
  5. mygov.scot — if a builder is doing the work for you
  6. nidirect — how to apply for Building Regulations approval
  7. gov.uk — register as a waste carrier, broker or dealer (England)
  8. Environmental Protection Act 1990, section 34 — duty of care
  9. Consumer Rights Act 2015, section 49 — reasonable care and skill
  10. Citizens Advice — more help with a consumer issue (England)
  11. Buildings and construction (VAT Notice 708) — 2.1 Construction services: work to an existing building is normally standard-rated
  12. GOV.UK — VAT rates
  13. GOV.UK — Register for VAT: when to register