Advice on Buying a Property with Private Drainage

For many homes, especially in rural areas or older developments, mains drainage isn’t available. Instead, properties may rely on private drainage systems like septic tanks, treatment plants, or even private water supplies.

Understanding these systems early in the buying process is essential to avoid unexpected costs, legal complications, or maintenance headaches.

Why Private Drainage Matters

Unlike mains sewers, private drainage systems are not maintained by the local authority. This means:

• Homeowners may be responsible for repairs and maintenance
• Shared systems may require cost contributions with neighbours
• Compliance with environmental regulations is essential
• Mortgage lenders often require confirmation that systems meet standards

When selling a property with private foul drainage, the seller is also obliged to inform the buyer (or the newly appointed responsible person) of the arrangements. This is covered by the Environment Agency’s General Binding Rules.

Overall, failure in compliance can delay your conveyancing process and even make the property unmortgageable.

Types of Private Drainage Systems

1. Septic tanks: Store waste on-site and require semi-regular emptying. The liquids drain away while solids remain.
2. Cesspit: Also stores waste on-site but is fully contained and therefore requires more regular emptying to prevent overflow.
3. Treatment plants: More advanced systems that treat wastewater before release
4. Shared systems: Serving multiple properties, requiring agreements for access and maintenance
5. Private water supplies: Wells or boreholes not connected to mains water

Regulatory Requirements for Private Drainage

Building Regulations

Since 1 January 2015, all private drainage systems require Building Regulations approval in England and Wales. This ensures the system is safe, structurally sound, and compliant with wastewater standards.

Even if planning permission is not required, all work must meet Building Regulations. A completion certificate should be obtained and kept for future resale or remortgage purposes.

Planning Permission

• Installing a new private drainage system may require planning permission from the local authority.
• Replacing an existing compliant system may not require permission.
• Check with your local council using the Local Authority Finder.

2020 Septic Tank Regulations

Since 1 January 2020, septic tanks in England must drain to ground, not directly into rivers, streams, or watercourses. Non-compliant systems should be updated to a sewage treatment plant or modified to meet the rule.

2023 Changes to General Binding Rules

From 2^nd October 2023, GBRs changes regarding small sewage discharges. These introduced:

• Combined Discharge Limits: New discharges must not share an outlet with another if their combined volume exceeds 5 cubic metres per day to surface water or 2 cubic metres per day to ground. If exceeded, an environmental permit is required.
• Proximity Restrictions: New discharges must be at least 50 metres away from any other discharge. If within this distance, a permit is necessary.

When to Engage a Solicitor

Before completing a purchase, a solicitor can:

• Check that you have legal rights to use and maintain the system.
• Verify that you have legal access rights to carry out work on the system if it is shared between neighbours, or your own but situated on a neighbour’s land.
• Review shared agreements with neighbours for cost and access obligations.
• Ensure compliance with environmental regulations.
• Advise on any lender requirements to avoid delays in financing.

Note that in England and Wales, conveyancing operates on a ‘buyer beware’ basis. As little information regarding private drainage is included in the Property Information Form, this means that the buyer’s solicitor must be proactive in raising any enquiries.

Practical Tips for Buyers

1. Ask about drainage early: Find out from the estate agent whether the property has mains connections or private systems.
2. Understand maintenance responsibilities: Know what costs and tasks will fall to you as the owner.
3. Check legal rights: Make sure you have formal rights to access and maintain any shared systems.
4. Factor in environmental rules: Some systems require regular inspections or compliance with local regulations.
5. Commission a drainage survey: Consider using a qualified private drainage expert to assess the arrangements.

Practical Tips for Sellers

Sellers should prepare before marketing:

1. Maintain service records and manuals for septic tanks, treatment plants, or cesspits.
2. Consider a pre-sale survey by a drainage expert.
3. Update non-compliant systems in advance, especially if a septic tank discharges to a watercourse.
4. Disclose all information to avoid delays or reduced sale value.

Visit our residential conveyancing page to learn more or get a quote.