Land drainage

• Advice regarding Run-off from Higher Ground to Lower Ground
• Legal Powers
• Ordinary Water Course Consenting and Enforcement
• Watercourse responsibilities
• Surface water drainage proposal checklist

Advice regarding run-off from higher ground to lower ground.

During extended wet periods, residents and communities occasionally report flooding from "natural" run-off from higher ground to lower ground. There is often an expectation from residents that councils, either West Sussex County Council or Chichester District Council will resolve these issues. Unfortunately, many of the issues sit with the landowner so to assist we have outlined the council's interpretation of the common law position for landowners.  All landowners, however, should seek their own legal advice.

The council's Interpretation of common law in relation to land drainage is as follows:

• Under common law, landowners have a right to 'natural' drainage. This means that water flowing naturally across the surface of the land is permitted to flow downhill, including over property boundaries and onto neighbouring land in different ownership.
• The exception to this rule is where the owner of the higher land has conducted alterations to, or undertaken the development of, their land, rendering the run-off produced by their land to no longer be considered 'natural'. The following are examples of when run-off would no longer be considered 'natural':
  • When a landowner has paved over previously permeable ground (such as grassland) with an impermeable surface (such as concrete) thus increasing the rate and volume of run-off from the higher land to the lower land.
  • When a landowner has constructed an impermeable structure on the land and the run-off from that structure flows towards the lower land, as a point discharge, from guttering downpipes etc.
  • Where a landowner has undertaken 'works on their land to 'channel' previously diffuse run-off onto neighbouring land.

Un-natural run-off, produced by the types of situations described above, must be appropriately controlled by the owner of the higher land (as the higher landowner must not increase flood risk beyond the boundary of their land). A lower landowner would be within their rights to object to, and reject, uncontrolled unnatural run-off from higher land. 

As well as the common law right for natural drainage outlined above (that a person owning lower-level ground must accept natural run-off, such as spring water, groundwater, or surface water run-off, from higher adjacent land), there is also a common law right that lower landowners should not take any action to prevent such natural flows entering their land.  There is an exception to this rule; all landowners have the right to take reasonable action to prevent their land being flooded.

Landowners who wish to undertake interventions to prevent the flooding of their land however be mindful of the following caveats:

• Preventative measures/works must not create a similar problem for a different landowner.
• Flow must not be directed/discharged onto the public highway (as this may be unlawful).
• All applicable permissions and consents, such as planning permission and/or ordinary watercourse consent, must be obtained prior to any such works being commenced (with the possible exception of emergency situations/measures). For consents and permissions to amend a watercourse, contact West Sussex County Council. If planning permission is required, contact your local planning authority which will either be South Downs National Park Authority, West Sussex County Council for major developments and Chichester District Council for minor developments.

What to do if you are affected by run-off from higher ground.

If run-off from higher ground is causing problems on your lower land, it is advisable to initially attempt to resolve the issue through communication and mediation with the neighbouring landowner, to see if a mutually acceptable resolution can be found. 

If the run-off in question is 'natural' run-off under common law, the owner of the higher ground may be under no obligation to alter the situation. However, if the run-off cannot be considered 'natural' then the following courses of action may secure an acceptable resolution:

• Civil Action may be possible; therefore, affected landowners may wish to seek their own legal advice and advice from an appropriately qualified drainage consultant/engineer.
• The local councils may be able to intervene, but this is only likely to be the case where the problematic run-off is a direct result of a contravention of planning law (where Chichester District Council or South Downs National Parks Authority would be the enforcing authority), or a breach of the Land Drainage Act (where West Sussex County Council would be the enforcing authority).

Legal powers

Chichester District Council has no statutory duty with regards to land drainage, except where we are the landowners. Historically, Chichester District Council had a role in land drainage, but this role was removed from the council by new legislation in 2012 when these powers were transferred to West Sussex County Council as the Lead Local Flood Authority. Between 2012 and 31 March 2025, West Sussex County Council arranged for the districts and boroughs in West Sussex to deliver this role, however from 1 April 2025, West Sussex County Council have taken this role back from the districts and boroughs.

This means that duties such as administering the ordinary watercourse/land drainage consents process, and the enforcement of the Land Drainage Act 1991 (in relation to ordinary watercourses) will be delivered by West Sussex County Council from the 1 April 2025. West Sussex County Council will have permissive powers to help ensure that:

• Watercourses are property maintained across the district
• Riparian landowners abide by the law and undertake their riparian responsibilities

If you have a land drainage problem, please contact the following; 

Ordinary water course consenting and enforcement

For all advice about ordinary watercourse consenting and enforcement, such as altering, infilling or culverting a watercourse, a blocked, infilled or poorly maintained watercourse - please contact West Sussex County Council Lead Local Flood Authority

Watercourse responsibilities

There are a number of different categories of watercourse and the category can affect where maintenance responsibilities lie:

• 'Main river' and/or 'critical ordinary watercourse'

These are watercourses that have been specifically classified by the Environment Agency for their strategic drainage importance.

Responsibilities lie with the landowner(s), but they are likely to be supported by the Environment Agency.

• Ordinary watercourse

These are open watercourses that have not been specifically classified as 'main rivers' or 'critical' by the Environment Agency.

Responsibilities lie with the riparian landowner(s).

• Culverted watercourses

These are piped sections of watercourses, where the water flows underground or beneath a structure/building or a crossing over the watercourse.

Responsibilities lie with the riparian landowner(s) or perhaps West Sussex County Council (if the culvert runs under the public highway).

• Highway gullies and drains

These are the drains on adopted roads that remove the excess surface water from the highway only.

Responsibilities lie with either West Sussex County Council or Highways England, depending upon the designation of the road.

• Sustainable drainage systems

These are surface water drainage systems designed and installed to drain surface water from a developed area.

Responsibilities can lie with; the developer, landowner or a management company.
 

Surface water drainage proposal checklist

The council has a duty to ensure that new developments do not increase flood risk and that surface water from the development is appropriately drained.  We have therefore developed a 'Surface Water Drainage Proposals Checklist' for planning applicants and their consultants.

The checklist is designed to clearly outline our expectations and requirements for 'Surface Water Drainage Proposals'. If applicants or their consultants submit a completed checklist with any surface water drainage proposals it will enable the council's drainage engineers to quickly and efficiently review and evaluate the submission.

The checklist can and should be used when completing 'discharge of conditions applications', or perhaps prior to that stage of the planning process should the applicant wish to avoid pre-commencement conditions relating to surface water drainage.

Before completing this checklist you are advised to read our 'Supplementary Requirements for Surface Water Drainage Proposals' document. 
 

Surface Water Drainage Proposals Checklist V5.3 (Word doc, 204 KB)