Pre-contract searches and enquiries - Water and drainage enq...

Learning Outcomes

This article outlines water and drainage enquiries in property transactions, including:

• Purpose and process of water and drainage enquiries
• Key legal issues: adoption status and flood risk
• Interpretation of CON29DW results
• Practical and contractual implications for clients
• Statutory rights and obligations affecting water and drainage
• Application to SQE1-style scenarios
• Distinction between foul and surface water arrangements
• Impact of the 2011 private sewer transfer on liability
• Build-over consents and sewer diversion agreements
• Compliance issues for private systems (including septic tanks) under the Environmental Permitting regime

SQE1 Syllabus

For SQE1, you are required to understand the role and significance of water and drainage enquiries as part of pre-contract due diligence in property transactions, with a focus on the following syllabus points:

• The purpose and process of water and drainage enquiries in conveyancing.
• The distinction between public and private water/sewer connections.
• The legal and practical implications of adoption status for drains and sewers.
• How flood risk and drainage issues affect property value, insurability, and marketability.
• Advising clients on risks, liabilities, and contractual protections relating to water and drainage.
• The requirement for build-over consents near public sewers, and the water company’s statutory access rights.
• Section 104 agreements, adoption bonds, and related standards (Design and Construction Guidance) for new sewers.
• Section 106 rights to connect to public sewers and Section 185 sewer diversion agreements.
• Sustainable drainage systems (SuDS), maintenance responsibilities, and how planning conditions interact with adoption.

Test Your Knowledge

Attempt these questions before reading this article. If you find some difficult or cannot remember the answers, remember to look more closely at that area during your revision.

1. What is the main purpose of a CON29DW water and drainage search in a property transaction?
2. What is the difference between an adopted and an unadopted drainage system, and why does it matter for a buyer?
3. How might the presence of a public sewer running beneath a property affect future development plans?
4. What are the key risks for a buyer if a property is not connected to the public sewer or water supply?

Introduction

Water and drainage enquiries are a standard part of pre-contract searches in property transactions. They provide essential information about a property's water supply, drainage arrangements, and related liabilities. For SQE1, you must be able to explain the process, interpret results, and advise clients on the legal and practical consequences of issues revealed by these enquiries. In practice, the water and drainage search complements the local search and environmental/flood searches: together, they inform on core questions—where water and wastewater go, who maintains the infrastructure, what consents are needed for future works, and how flooding or contamination risks might affect value, insurance or lending.

Water and Drainage Enquiries: Purpose and Process

A water and drainage enquiry is usually made by submitting a CON29DW form to the local water company. The search result confirms whether the property is connected to the public water supply and public sewer, and provides details about the location and adoption status of relevant infrastructure.

Key Term: CON29DW search
A standard enquiry submitted to the local water company to establish water supply and drainage arrangements for a property.

The search typically reveals:

• Whether the property is connected to public mains water.
• Whether foul water drains to a public sewer and whether surface water drains to a public sewer, watercourse, or soakaway.
• The location of public sewers and water mains in proximity to or within the property boundary (from statutory records).
• Whether the property has any recorded history of internal or external sewer flooding due to hydraulic overload.
• Whether water is metered and basic supply information.
• Any build-over restrictions or requirements (often highlighted where public sewers are nearby).

The search result helps identify potential risks, costs, and restrictions that could affect the buyer's use and enjoyment of the property. If red flags appear—such as lack of connection, sewer flooding records, or public sewers under proposed extension footprints—raise targeted enquiries and consider specialist surveys.

Public vs Private Connections

A key issue is whether the property is connected to public (adopted) or private (unadopted) water and drainage systems.

Key Term: adopted drainage system
A drain or sewer that is maintained at the expense of the local water company, following a formal adoption agreement.

Key Term: unadopted drainage system
A drain or sewer that remains the responsibility of the property owner(s) for maintenance and repair.

If a property is not connected to the public sewer or water main, the owner may face significant costs for repairs, upgrades, or eventual adoption. Private drainage systems (such as septic tanks) may also require compliance with environmental regulations.

Post-2011, many formerly private shared sewers and lateral drains transferred to the statutory undertakers under the Water Industry (Schemes for Adoption of Private Sewers) Regulations 2011. In general:

• Drains within the curtilage serving only a single property often remain private (owner-maintained).
• Lateral drains (between the property boundary and the public sewer) and shared sewers usually became public and are maintained by the water company.
• Pumping stations serving multiple properties transferred later (broadly by 2016), reducing collective private liabilities.

Understanding which parts are still private is important for maintenance responsibility and cost.

Key Term: lateral drain
A pipe carrying wastewater from a property to a public sewer, located outside the property boundary. Frequently public and maintained by the water company following the 2011 transfer.

Adoption Status and Section 104 Agreements

Where a property is part of a new development, drains and sewers may not yet be adopted. In such cases, a Section 104 agreement under the Water Industry Act 1991 is often in place, obliging the developer to bring the system up to standard for adoption.

Key Term: Section 104 agreement
A legal agreement between a developer and the water company for the adoption of new sewers, making the water company responsible for future maintenance once adoption is complete.

Key Term: adoption bond
A financial guarantee provided by a developer to the water company to ensure completion of works required for adoption of new sewers.

If no Section 104 agreement or adoption bond exists, the buyer may be at risk of future charges to bring the system up to standard or ongoing maintenance liabilities.

Practical points:

• Confirm the existence and validity of the Section 104 agreement and bond.
• Check whether the sewers have reached “adoptable standards” (per the current water industry Design and Construction Guidance).
• Identify who maintains SuDS components on the estate (some SuDS features are not adopted by water companies and remain with a management company).

Key Term: sustainable drainage systems (SuDS)
Drainage features designed to mimic natural runoff (e.g., swales, attenuation basins, permeable surfaces). SuDS can reduce flood risk and improve water quality. Adoption varies; many SuDS features are maintained by local authorities or management companies rather than water companies.

Worked Example 1.1

A buyer is purchasing a new-build house. The CON29DW search reveals that the foul water drain is not yet adopted, but a Section 104 agreement is in place. What should the buyer's solicitor advise?

Answer:
The solicitor should confirm that a valid Section 104 agreement and adoption bond exist, ensuring the developer is responsible for bringing the drain up to standard for adoption. The buyer should be warned not to alter the drainage system before adoption, as this could jeopardize adoption or insurance. Advise on estate management charges for any unadopted SuDS features and confirm whether the lender requires evidence of both s104 and appropriate arrangements for estate roads and sewers.

Public Sewers and Development Restrictions

The search result will show if a public sewer runs within the boundaries of the property. This is important because water companies have statutory rights of access to maintain public sewers, and building over or near a public sewer usually requires the water company's consent.

Key Term: public sewer
A sewer that is maintained by the local water company and to which the public has a statutory right of connection.

Key Term: build-over agreement
Formal consent from the water company to build over or within a specified distance (commonly 3 metres) of a public sewer.

Key Term: build-over risks
The legal and structural risks of constructing over or near a public sewer without consent, including enforcement action, future access requirements, and potential demands to alter or remove structures.

If a buyer intends to extend or develop the property, the presence of a public sewer may restrict those plans or require additional permissions. Water companies’ rights of access and protection of sewers can affect layout, foundations, and timing. In some cases, developers enter a Section 185 agreement to divert public sewers at their cost.

Key Term: Section 185 sewer diversion
An agreement under the Water Industry Act 1991 allowing for diversion or alteration of public sewers, generally at the developer’s expense and subject to water company approval.

Key Term: Section 106 connection
A statutory right and process under the Water Industry Act 1991 for property owners to connect drains or sewers to the public sewer network, subject to compliance and fees.

Worked Example 1.2

A client wants to build an extension. The CON29DW search shows a public sewer runs under the proposed extension site. What is the risk?

Answer:
The client will need the water company's consent to build over or near the sewer. Without consent, the extension may be unlawful, and the water company could require removal or alteration of the structure. In some cases, a diversion (s185) may be required. Obtain a build-over agreement and verify the precise sewer location (statutory maps are indicative) before design and construction.

Flood Risk and Drainage

Water and drainage searches may also highlight flood risks, especially if the property is in an area prone to surface water flooding or if drainage is inadequate.

Key Term: flood risk
The likelihood that a property will be affected by flooding from rivers, surface water, groundwater, or sewers.

Flood risk can affect insurability, mortgageability, and property value. Buyers should be advised to obtain specialist flood searches and check insurance availability if a risk is identified. Sewer flooding due to overloaded public sewers is an important indicator in CON29DW results; repeated incidents can affect insurability and could suggest network capacity issues that constrain future development.

Best practice:

• Consider a dedicated flood search (covering river, coastal, surface and groundwater risk) in addition to the water company’s sewer flooding records.
• If SuDS are present, clarify long-term maintenance and funding (e.g., estate rentcharges to fund management), and any performance or capacity issues reported by the water company or local authority.

Maintenance and Repair Liabilities

If the property is served by unadopted drains or private systems (such as septic tanks or soakaways), the owner is responsible for maintenance and repair. This can be costly and may require compliance with environmental permits or regulations.

Key Term: private drainage system
A drainage arrangement (such as a septic tank or soakaway) that is not connected to the public sewer and is maintained at the owner's expense.

Where private systems discharge to watercourses, the Environmental Permitting (England and Wales) Regulations 2016 and the Environment Agency/Natural Resources Wales guidance apply. In England, the General Binding Rules restrict septic tanks discharging directly to surface water: many require upgrade (e.g., to a package treatment plant) or alternative arrangements. Buyers must ascertain:

• The type of system, location, age and capacity.
• The discharge route (ground infiltration vs watercourse).
• Service, maintenance, and compliance records.
• Any permits required and evidence of compliance with General Binding Rules.

For mixed arrangements:

• Private drains within the curtilage serving one property remain owner-maintained.
• Lateral drains and shared sewers are often public, reducing owner liabilities.
• Misconnections (e.g., surface water wrongly connected to foul) can generate enforcement action and remedial costs.

Key Term: adoption bond
A financial guarantee provided by a developer to the water company to ensure completion of works required for adoption of new sewers.

If the system is not up to standard, the owner may face enforcement action or be required to pay for upgrades before adoption. For commercial properties, trade effluent discharges require consent from the water company; failure to obtain consent risks enforcement and operational disruption.

Practical Advice for Clients

Solicitors should review the CON29DW result and raise additional enquiries if:

• The property is not connected to the public sewer or water main.
• The drains or sewers are unadopted and no Section 104 agreement or adoption bond is in place.
• A public sewer runs within the property boundary.
• Flood risk or surface water drainage issues are identified.
• The property relies on private systems (e.g., septic tank, package treatment plant, soakaway) or on SuDS whose maintenance is by a third party.
• There is any mention of sewer flooding incidents affecting the property or locality.
• Future development is contemplated (extensions, conversions), and build-over constraints or diversion needs are likely.

Documentation to request and review:

• Any build-over agreements or sewer diversion consents.
• Section 104 agreement and adoption bond details; confirmation of progress toward adoption and inspection reports.
• SuDS approvals/maintenance schedules; management company obligations and estate rentcharge documentation.
• Septic tank/package plant maintenance logs, compliance certificates, and permits.
• Evidence of Section 106 connection, if recent works were made to connect to the public sewer.

Contractual protections may include retention of funds pending adoption, warranties/indemnities from the seller/developer, or targeted indemnity insurance (e.g., absence of build-over consent, private drainage non-compliance). Where lenders are involved, note UK Finance Handbook expectations on roads/sewers adoption and consider reporting any non-standard arrangements.

Worked Example 1.3

A buyer discovers that the property is served by a private septic tank. What issues should the solicitor raise?

Answer:
The solicitor should advise the buyer to check that the septic tank complies with environmental regulations, is in good working order, and that maintenance arrangements are clear. The buyer should be aware of potential costs for repairs or replacement. Establish discharge route (surface water vs ground), verify compliance with General Binding Rules or any permit, obtain servicing records and capacity information, and confirm rights of access for maintenance (particularly if any part of the system lies on third-party land).

Worked Example 1.4

A seller extended their kitchen five years ago. The CON29DW result shows a public sewer crossing beneath the extension. No build-over agreement can be produced. What is the risk and how can you manage it?

Answer:
Absence of a build-over agreement poses legal and practical risks: the water company may require inspection, could demand remedial works, and retains access rights which may disrupt the property. Options include seeking retrospective consent (often requiring CCTV survey and structural verification), obtaining indemnity insurance (subject to no contact with the water company), and negotiating a retention to cover potential remediation. Report the position to any lender.

Worked Example 1.5

A small developer proposes to relocate a shallow public sewer to free up the plot layout. What process is likely required and who bears the cost?

Answer:
A Section 185 sewer diversion agreement is typically required, with design approval by the water company. The developer bears costs (design, construction, supervision, and any service disruption management). Timing and technical constraints should be factored into the build program.

Exam Warning

If the property is not connected to the public sewer or water main, or if the drains are unadopted, the buyer may face significant future costs. Always check for a valid Section 104 agreement and adoption bond, and advise on the risks of private drainage.

Revision Tip

Always review the CON29DW result alongside other searches and the property information form. Raise specific enquiries if any issues or uncertainties arise.

Key Point Checklist

This article has covered the following key knowledge points:

• Water and drainage enquiries are a standard pre-contract search in property transactions.
• The CON29DW search confirms connections to public water and sewer systems and identifies adoption status.
• Adopted systems are maintained by the water company; unadopted systems are the owner's responsibility.
• Section 104 agreements and adoption bonds protect buyers in new developments.
• The presence of a public sewer may restrict development and require water company consent (build-over), with diversion possible under Section 185.
• Private drainage systems (e.g., septic tanks) require compliance with environmental regulations and ongoing maintenance.
• Flood risk identified in searches may affect insurance and value; sewer flooding records in CON29DW are significant.
• Following the 2011 private sewer transfer, many liabilities shifted to water companies; drains within the curtilage serving a single property may remain private.
• SuDS features may not be adopted by water companies and may be maintained by management companies; clarify estate charges and maintenance obligations.
• Solicitors should advise clients on risks, costs, and contractual protections related to water and drainage issues, including build-over agreements and Section 106 connections.

Key Terms and Concepts

• CON29DW search
• adopted drainage system
• unadopted drainage system
• Section 104 agreement
• adoption bond
• public sewer
• build-over agreement
• build-over risks
• Section 185 sewer diversion
• Section 106 connection
• flood risk
• private drainage system
• lateral drain
• sustainable drainage systems (SuDS)