Off-mains drainage · Chelmsford & Essex

Septic Tank Replacement & Sewage Treatment Plants

If your septic tank discharges to a ditch, stream or other watercourse, the general binding rules say it must be replaced or upgraded. We install sewage treatment plants for homes in Chelmsford and surrounding villages, and for farms and commercial properties across Essex.

Homeowners: Chelmsford and surrounding villages · Commercial and industrial: Essex, London and nationwide

Get a free quote Call 07904 792345 WhatsApp

Sewage treatment plant and inspection chambers installed in a gravel bed with orange drainage pipework

Replacing a septic tank with a sewage treatment plant

A sewage treatment plant treats waste water to a higher standard than a septic tank. If your property is not on the mains sewer and your septic tank discharges to a watercourse, replacing it with a treatment plant is one of the ways to meet the rules.

We carry out the groundwork for sewage treatment plant installation for homes in Chelmsford and surrounding villages and for farms and commercial properties across Essex, from digging out to reinstating the ground. See also our groundwork and drainage services.

What our installation work covers

Excavating the pit to the depth the plant needs
Preparing the base, such as a concrete base where required
Setting the plant level and connecting the pipework
Installing inspection chambers
Backfilling and reinstating the ground
Leaving the area safe and tidy

The general binding rules in plain English

The Environment Agency’s general binding rules for small sewage discharges in England (often called the 2020 rules) set out what septic tanks and treatment plants must do to operate without a permit. In short:

Septic tanks must not discharge straight to a watercourse. If yours discharges directly to a river, stream, ditch or other watercourse, you must connect to a public foul sewer, replace the septic tank with a small sewage treatment plant, or install a drainage field.
Timescale. GOV.UK says to do this as soon as possible, with plans in place to do the work within a reasonable timescale, usually 12 months.
House sales. If a property with a septic tank discharging directly to a watercourse is bought or sold, the buyer and seller should agree who is responsible for replacing or upgrading it, as a condition of sale. That is why it is often flagged during a sale.
Approvals. A new sewage treatment plant needs Building Regulations approval, and may also need planning permission.
Newer discharges. Discharges that started or changed on or after 2 October 2023 have extra rules (GOV.UK: new discharges).

This is a plain-English summary, not legal advice. Read the full guidance on GOV.UK: general binding rules, small sewage discharge to a surface water.

Sewage treatment plant installation

A recent installation in Essex: the excavation with its concrete base, then the plant and inspection chambers in place.

Deep square excavation pit with a freshly poured concrete base, ready for a sewage treatment plant — Excavation with concrete base

Inspection chamber with cover connected to orange drainage pipework in a gravel bed — Inspection chamber and pipework

Sewage treatment plant installation across Essex

Septic tank replacement FAQs

Does my septic tank need replacing?

Under the Environment Agency’s general binding rules, if your septic tank discharges directly to a watercourse such as a river, stream or ditch, you must connect to a public foul sewer, replace the septic tank with a small sewage treatment plant, or install a drainage field. Different rules apply to tanks that discharge to the ground. If you are not sure where yours discharges, GOV.UK suggests getting advice from a competent service engineer.

How long do I have to do the work?

GOV.UK says the work should be done as soon as possible, and that you must have plans in place to do it within a reasonable timescale, usually 12 months.

I am buying or selling a house with a septic tank. What happens?

GOV.UK says that if a property with a septic tank discharging directly to a watercourse is bought or sold, the buyer and seller should agree who will be responsible for replacing or upgrading the system, as a condition of sale. This is why it often comes up during a house sale.

Do I need Building Regulations approval?

Yes. GOV.UK says you must have Building Regulations approval to install a new sewage treatment plant, and you may also need planning permission. Check with your local council’s Building Control.

What does your installation work include?

We carry out the groundwork for sewage treatment plant installation: excavating the pit, preparing the base, setting the plant in place, installing inspection chambers and laying the drainage pipework, then backfilling and reinstating the ground.

What happens to the old septic tank?

GOV.UK says that when you stop using a septic tank, anything that could cause pollution, such as remaining sludge, must be removed so it is decommissioned properly. We will talk through what your site needs when we quote.

Are you insured?

Yes. We carry £10 million public liability insurance. We are also a registered waste carrier, and machine work is carried out by an experienced operator.

How do I get a quote for septic tank replacement?

Call or WhatsApp us on 07904 792345, email james.southeastservices@gmail.com, or use the quote form on our contact page. Photos of the job are helpful. Our opening hours are Monday to Friday, 8:00am to 5:30pm.