Surface water runoff law UK: who is responsible?

Water flowing into your garden or towards your home can be worrying, particularly when the problem only appears during periods of heavy rain.

It may seem clear that the water is coming from a neighbouring property, but identifying who is legally responsible is not always straightforward. 

The position may be different when building work, landscaping, paving or changes to drainage have increased or redirected the flow of water. In these circumstances, surface water runoff can lead to a property dispute.

This guide explains the law relating to surface water runoff in England and Wales, when a neighbour may be responsible and the steps you can take if water is damaging your property.

Table of contents - Jump to specific sections below

• What is surface water runoff?
• Who is responsible for surface water runoff?
• Does a lower property have to accept water from higher land?
• When could a neighbour be responsible for surface water runoff?
• What legal claims can arise from surface water runoff?
• Who is responsible for private drains and soakaways?
• Can you block water entering your property?
• What evidence should you collect?
• Should you obtain a drainage report?
• What should you do if a neighbour's water is flooding your property?
• What if surface water is running off the road?
• How Battens Solicitors can help

What is surface water runoff?

Surface water runoff is rainwater that does not soak into the ground or enter a suitable drainage system. Instead, the water collects or flows over the surface of the land.

This is sometimes referred to as surface water flooding or pluvial flooding.

Surface water runoff can be caused or made worse by:

• prolonged or heavy rainfall;
• saturated or compacted soil;
• paved driveways and patios;
• extensions and other buildings;
• changes to the height or slope of land;
• blocked drains, ditches or culverts;
• downpipes or drainage channels; and
• walls, embankments or other structures that change the water’s route.

One incident may have more than one cause. For example, heavy rain might overwhelm the drainage available, while paving on a neighbouring property increases the amount of water flowing towards your land.

Who is responsible for surface water runoff?

There is no single answer. Responsibility will depend on where the water came from, how it reached the affected property and whether anything, such as paving, building work or altered drainage, increased or redirected its flow.

Establishing the cause may require evidence from a drainage specialist, surveyor or other suitably qualified experts.

Does a lower property have to accept water from higher land?

Rainwater will naturally follow the slope of the land. As a general starting point, an owner of lower land has to accept water that arrives through the ordinary, natural drainage of higher land.

A neighbour is therefore not automatically responsible simply because rain falling on their garden or adjoining land, such as a field, eventually reaches your property.

However, there is a difference between water flowing naturally and somebody collecting, concentrating or redirecting it.

For example, water spreading gradually across a sloping lawn may be part of the natural drainage of the land. Water collected by a pipe, ditch or hard surface and discharged at one point near a neighbouring property is a different situation.

The circumstances of each property will need to be considered carefully. The natural lie of the land, previous drainage arrangements and any recent alterations can all be important.

When could a neighbour be responsible for surface water runoff?

A neighbour may be responsible if something they have done, or failed to address, has increased or redirected water flowing onto your property.

Examples may include:

• laying impermeable paving without suitable drainage;
• changing the level or slope of a garden;
• building an extension, raised patio or terrace;
• directing a downpipe, pipe or drainage channel towards adjoining land;
• blocking a ditch, drain or natural flow route;
• failing to maintain private drainage; or
• constructing a wall or embankment that diverts water.

If the flooding began after nearby building or landscaping work, this may need to be investigated. However, timing alone does not prove responsibility, as rainfall, blockages or other drainage problems may also have contributed.

What legal claims can arise from surface water runoff?

Depending on the circumstances, a surface water dispute may involve several legal principles.

Private nuisance

Repeated flooding, substantial waterlogging or property damage may amount to private nuisance where a neighbour’s use of their land unreasonably interferes with your property.

Relevant factors include the cause and frequency of the flooding, the extent of the damage, whether it was foreseeable and whether the neighbour’s actions changed the flow of water. Evidence linking their actions or property to the problem will usually be required.

Trespass

Trespass may be relevant if, for example, a pipe is laid across a boundary or equipment is placed on another person’s land without permission.

However, the title documents should be checked, as a legal right to use a drain or discharge water may already exist through an easement or another arrangement.

Who is responsible for private drains and soakaways?

According to GOV.UK guidance on reporting flooding, flooding caused by a private drain is generally the property owner’s responsibility. Problems involving public sewers or burst water mains should be reported to the relevant water company.

A private drain or soakaway may cause a dispute if it is:

• blocked, damaged or poorly maintained;
• too small for the area it serves; or
• discharging water in an unsuitable location or onto neighbouring land.

Before attributing responsibility, establish whether the drain is private, shared or part of the public sewer network. Property deeds, drainage plans, a CCTV drainage survey and information from the water company may help.

Can you block water entering your property?

You can take reasonable steps to protect your property, but any work must not redirect water, increase flooding elsewhere, obstruct a watercourse or interfere with an existing drainage right.

Protective measures may include drainage channels, raised thresholds, flood barriers, rain gardens or landscaping. Relevant permission may be required, so seek professional drainage advice before carrying out work that could significantly alter the water’s route.

What evidence should you collect?

Surface water may disappear before the problem can be inspected, so record the flooding while it is happening, provided it is safe to do so.

Useful evidence includes:

• photographs and videos showing the direction and extent of the water;
• the date, time, weather conditions and duration of each incident;
• evidence of damage and resulting costs;
• photographs taken before and after nearby building or landscaping work;
• planning documents and drainage reports;
• correspondence with neighbours, contractors, insurers or relevant authorities; and
• reference numbers for any reports made.

Include fixed features, such as walls, doors or fences, in photographs to show the water’s location and scale. Keep a chronology of when the problem began, how often it occurs and any work that may have affected the drainage.

Should you obtain a drainage report?

A drainage engineer, surveyor or flood specialist may be needed if the source of the water is unclear or responsibility is disputed.

Expert evidence can help establish the cause and extent of the damage, identify a practical solution and support a claim if court proceedings become necessary. Do not enter neighbouring land or carry out investigations there without permission. The courts expect neighbours to try and cooperate over the evidence, and often it will be appropriate to propose the neighbours jointly instruct a single joint expert to keep down litigation costs.

What should you do if a neighbour's water is flooding your property?

1. Record the flooding

Take photographs and videos while the flooding is happening, if it is safe to do so. Keep a record of each incident and the damage caused.

2. Establish the likely source

Consider whether the problem followed nearby paving, building, landscaping or drainage work. The most visible source may not be the actual cause.

3. Speak to your neighbour

Explain what is happening without immediately making allegations. Your neighbour may not know that their land or drainage is affecting your property.

4. Notify your insurer

Contact your buildings or contents insurer promptly. Check whether your policy covers legal expenses or expert investigations.

5. Obtain professional advice

A drainage specialist may identify the cause and recommend remedial work. Legal advice can help establish whether you can require action or recover your losses.

6. Keep written records

Retain letters, emails and messages. Follow up important conversations with a polite written summary.

7. Consider negotiation or mediation

A dispute may be resolved by agreeing drainage work, access arrangements or a contribution towards repairs. Mediation can help the parties find a solution without immediately going to court.

What if surface water is running off the road?

Flooding from a public road or drain should be reported to the relevant local council. Blocked public sewers and burst water mains should be reported to the water company.

Highway authorities have powers under Section 100 of the Highways Act 1980 to provide and maintain highway drainage. However, water coming from the direction of a road does not automatically make the highway authority responsible. The source may involve highway drainage, private land, a ditch, watercourse or public sewer.

Keep:

• the report reference number;
• photographs of flooding or blocked gullies;
• copies of correspondence;
• records of previous incidents; and
• details of any inspection or response.

How Battens Solicitors can help

Our Property Dispute Resolution team can advise on disputes involving runoff from neighbouring land, flooding following building or landscaping work, altered land levels, drainage systems, watercourses, property damage and applications for injunctions.

We take a practical approach, helping you establish the cause, understand your legal position and find the most appropriate way to resolve the dispute.

Get in touch with our Property Dispute Resolution team based in our Yeovil and Bath offices by calling 0800 652 8373 or by emailing [email protected].