Free Septic Tank Upgrade Scheme

WCI’s Free Upgrade Scheme offers eligible homeowners in Somerset a completely free replacement of their existing septic tank with a modern, fully compliant Graf sewage treatment plant. There is no cost to the homeowner for the installation. The scheme is funded by developers who need to purchase phosphate credits to satisfy nutrient neutrality planning conditions in the Somerset Levels and Moors catchment area. When WCI installs a new sewage treatment plant and decommissions the old septic tank, the improvement in wastewater treatment quality generates the phosphate credits that developers need.

Yes – there is no charge to the homeowner for the installation of the new sewage treatment plant. The scheme covers the full cost of supply, installation and decommissioning of the old system. Please note that the scheme does not cover additional drainage work that may be required outside of the core installation scope – for example, removing rainwater connections from the foul drain, replacing damaged pipework upstream of the tank, or remedying failed drainage fields. If a site survey reveals that additional work is needed before installation can proceed, we will advise you and provide a separate quote for that work.

The scheme is funded by developers who require phosphate credits to satisfy nutrient neutrality conditions attached to their planning consents within the Somerset Levels and Moors Ramsar catchment. When WCI upgrades a septic tank to a sewage treatment plant, the measurable reduction in phosphorus loading generates phosphate credits that can then be allocated to a developer’s planning mitigation. The homeowner pays nothing because the developer purchasing the credits is effectively covering the cost of the upgrade.

WCI has over 40 years of established presence in Somerset’s water and wastewater sector. We install, service, and maintain thousands of systems across the region. Our Managing Director, Brad Taylor, pioneered this upgrade credit model – an innovation now replicated nationwide. We are here for the long term.

To qualify for the scheme, you must: own a residential property with an existing septic tank; be located within an eligible catchment area in Somerset; and be willing to enter into a legal agreement with the Council committing to the ongoing maintenance of the new system. The scheme currently applies only to residential properties – it does not cover businesses, village halls, church halls or other non-residential uses, though residential properties with some commercial use (such as residential care homes) may be considered on a case-by-case basis.

Because the eligible areas do not neatly follow postcode boundaries, the simplest way to find out if your property qualifies is to register your interest and we will check your location using our mapping system.

Eligible areas do not follow postcode boundaries neatly. The quickest way to check is to register your interest – we’ll confirm your location using our mapping system advised by Natural England. There is no obligation at this stage.

Shared systems can be upgraded. However, all owners whose properties feed into the shared tank must register and agree to proceed – we cannot advance the upgrade for one property if another owner declines. If you wish to separate your drainage from your neighbour’s, this may be possible where a technically suitable separate discharge point exists, and we will assess this during the site survey.

Please speak to your neighbours before contacting us – we are not able to negotiate with them on your behalf.

Most installations take between three and five working days. Here is what to expect:

Day 1: The installation team arrives, establishes site setup, and delivers equipment

Days 2–4: Excavation, tank installation, pipework connections, and electrical hookup

Day 5: Final connections, commissioning, testing, and handover

You do not need to be home throughout. We bring portable toilet facilities so you’re never without access. Working areas are controlled to minimise disruption, and excavated areas are restored to a level finish on completion.

We ask that you minimise heavy water usage – such as running multiple laundry loads – for approximately 48 hours while the system is being connected.

Your old septic tank will be emptied and decommissioned. Where it is close to the installation position of the new system, it will typically be infilled with compressible material and the area levelled. If the new system must be installed in exactly the same location, the old tank will be excavated and disposed of responsibly.

Once complete, the only visible above-ground element is a small compressor housing – similar in appearance to a ventilation unit – positioned near a wall, hedge, or outbuilding. You will also see one or two new inspection covers at ground level. The installation area will be left level and tidy.

WCI does not re-landscape, re-seed, or re-turf gardens following installation under the scheme – you will need to finish the garden to your own preference or request this as a quoted job.

In almost every case, you will continue to have full use of your foul drains throughout the installation. We provide portable toilet facilities on site as an additional measure.

WCI installs Graf sewage treatment plants under the free upgrade scheme. Graf is a German manufacturer and their treatment plants are approved by Natural England for use in nutrient neutral areas under this type of scheme. The system is sized according to your property and in line with current Building Regulations.

Yes. The Graf sewage treatment plant installed under the scheme comes with a 15-year warranty on the tank itself and a three-year warranty on all serviceable parts, both provided by the manufacturer, Graf.

Yes. WCI supplies and installs the system at no cost to you, but ownership transfers to you on completion of the works. It is yours in the same way your boiler or roof is yours – it will need routine maintenance over its operational life.

The performance difference is dramatic:

• Old septic tank: typically discharges 1.5–2.5 kg of phosphate annually

• Modern treatment plant: discharges less than 0.1 kg of phosphate annually – a reduction of over 95%

Beyond phosphates, modern treatment plants are simply more effective across the board: better treatment of all pollutants, more reliable operation, better handling of variable loads, and full compliance with current environmental standards.

WCI produces a Technical Mitigation Report (TMR) demonstrating the phosphate reduction for council approval – this proves the environmental benefit is real and measurable.

When you proceed with installation, you will sign a document called a Unilateral Undertaking. The name sounds daunting, but it is simply a formal agreement with Somerset Council that confirms:

• You will maintain the upgraded system in good working order

• You will allow annual discharge monitoring (WCI carries this out free of charge for the first five years)

• You will only replace the system with one offering equivalent or better treatment

• You will allow the Council access on 21 days’ notice to inspect the system

• These obligations transfer to future owners if you sell the property

The agreement is registered with the council and runs with the land – meaning any future owner of your property will inherit the same obligations.

In practice, it simply means keeping up with the standard maintenance any treatment plant requires: annual servicing and periodic desludging every two to three years. Nothing unusual or burdensome.

Failure to maintain constitutes a breach of covenant, which the council can enforce. In practice, problems are rare – proper maintenance is straightforward and the annual service is quick and routine.

Yes – at any point before signing the Unilateral Undertaking, and with no financial charge. Once signed, you are committed for the system’s design life. However, if you later sell the property, the obligations simply transfer to the new owner and we update our records accordingly.

There are three main costs to factor in:

• Electricity: Running costs equate to less than a 60-watt lightbulb running continuously – approximately £65 per year for an average domestic property

• Desludging: Every 2–3 years, similar to a standard septic tank emptying. You can use any licensed waste contractor, including the one you already use      

• Annual servicing: Required by law under the Environment Agency’s General Binding Rules. Typically around £150 + VAT per year.

Yes. Under the Environment Agency’s General Binding Rules, all sewage treatment plants – whether installed through our scheme or purchased privately – must be serviced annually by a competent person. Think of it like an MOT for your car: essential maintenance that keeps everything working safely and legally. This obligation exists for any treatment plant owner under current environmental law.

Yes – you are free to use any approved contractor for annual inspections and maintenance. WCI Service Engineers offer this service (and know the systems inside out, having installed them), but your choice of provider is never required and is entirely yours.

The survey, equipment, and installation are entirely free. However, a small number of situations involve additional costs that the scheme does not cover:

Solicitor fees

Most homeowners proceed without needing a solicitor. However, if your mortgage lender requires you to instruct one regarding the Unilateral Undertaking, any legal fees are between you, your solicitor, and your lender. WCI does not require you to use a solicitor.

Pre-existing drainage problems

If your current foul drainage has a fault that requires repair before the new system can connect – such as cracked pipes or collapsed drains – you would need to arrange and fund that repair separately. Our site survey identifies any such issues upfront, so there are no surprises.

Rainwater diversion

Many older septic tanks incorrectly receive rainwater from roof gutters mixed with foul water. Current regulations require these to be separated. If your existing guttering discharges into your septic tank, you will need to arrange diversion to a suitable soakaway before installation begins. This is usually straightforward groundwork.

Third-party land access

If installation requires crossing a neighbour’s land beyond our standard access agreement, any additional costs or arrangements are between you and that landowner. We always discuss foreseeable requirements during the survey.

The upgraded system and its maintenance obligations transfer to the new owner on sale – we simply update our records. This does not negatively affect your property’s value or saleability. You are transferring a modern, compliant wastewater system, which most buyers view positively, particularly in areas where septic tank replacement costs are a concern for purchasers.

Your solicitor will disclose the Unilateral Undertaking during conveyancing. If you let us know ahead of sale, we will update our records with the new owner’s details.

Mention this during the survey. We can design system capacity to accommodate planned extensions, ensuring your upgraded system won’t limit future development. If extensions arise after installation, contact us – many systems have spare capacity, or modifications may be possible.

Does the upgrade affect my council tax?

The Free Upgrade Scheme is not designed to respond to urgent or emergency situations. Funding for the scheme is directly linked to developer activity in the Somerset Levels and Moors catchment, and current market conditions – combined with a policy change allowing developers to receive planning consent without first securing a Reservation Notice – have significantly slowed the release of upgrade funding. A substantial wait is currently expected for scheme upgrades.

If your current system is failing and you cannot wait, WCI can still help – we have over 40 years of experience in off-mains drainage and can carry out a fast, fully funded paid installation outside of the free upgrade scheme. Contact us to discuss your options.

WCI Service Engineers can help keep your existing system functioning reliably in the meantime:

• Routine servicing to prevent breakdowns

• Compliance surveys if required for property transactions

• Smell investigations if you’re experiencing odour issues

• Rectification work for ageing systems in need of repair

Or, if you’d prefer not to wait, WCI Project Engineers can quote a paid installation with no waitlist – contact us on 01984 623 404.

No. If you decide not to proceed with an upgrade, or if your property does not qualify for the scheme, your details will not be shared with any third party. All personal data is held securely in line with our privacy policy.

Every system has emergency contact details displayed on the kiosk for urgent issues. For routine questions or service scheduling, contact WCI Service Engineers: 01984 623 404.