Owning a watercourse

Find out if you own a watercourse

You normally own a stretch of watercourse that:

  • runs on or under your land
  • on the boundary of your land, up to its centre

Check the deeds of your property if you are not clear about ownership.

If you rent the land, you should agree with the owner who will manage these rights and responsibilities.

A watercourse can be a:

  • river
  • brook
  • beck
  • ditch
  • mill
  • stream
  • culvert (an underground structure that water can flow through)

Report an incident

Contact us about incidents on 'main rivers'. Main rivers are usually larger rivers or streams.

Report and incident online or by phone to tell us about:

  • flooding
  • blockages that could cause flooding on a main river
  • pollution
  • collapsed or damaged banks
  • unusual changes to the river flow

Your responsibilities

Let water flow naturally

You must let water flow through your land without any obstruction, pollution or diversion.

Leave space around the watercourse for access, in case maintenance or inspection is needed.

River blockages 

You must keep the banks clear of anything that could cause an obstruction or increase flood risk, either on your land or downstream. For example, fallen trees or low hanging branches. You should leave all other trees, branches and shrubs - they can help prevent flooding and reduce erosion. 

keep any structures, such as culverts, trash screens, weirs and mill gates, clear of debris.

Do not go inside a culvert as you could become trapped or poisoned by gases. If it needs clearing or repairing, contact your risk management authority for advice.

Protect wildlife

Prevent pollution

You must not pollute the water. Do not use riverbanks to dispose of garden waste, waste water, chemicals, or anything else that could cause pollution. 

You should:

  • clear any litter from the banks
  • remove animal carcasses from the channel and banks, even if they did not come from your land

Find out about the legal rules on using herbicides.

Reduce erosion

You are responsible for protecting riverbanks from erosion. Check the guidance below to see if you need a licence before starting any work.

Contact your risk management authority if you are concerned that the erosion is affecting a flood defence.

Get advice about owning a watercourse

For advice about what you must do if you own a stretch of watercourse, contact your risk management authority.

If it’s about:

  • a main river or an internal drainage district, we are your risk management authority and you should contact us
  • any other watercourse, your risk management authority is your lead local flood authority 

Managing your flood risk

If you own a watercourse you have a responsibility to check your flood risk. You can:

Flood defence or other structures on your land

Structures on your land, such as a wall or culvert, may be important to prevent flooding. 

If a flood defence structure runs through your property, you would own it from the point that that it enters your land to the point that it leaves. You may be responsible for maintaining, repairing, and replacing the structure. 

Check who owns and maintains flood defence structures near you

Get permission to do work in or around a watercourse

You need to find out which permissions and licences you need before carrying out any work in or around a watercourse. This includes:

  • dredging
  • changing the riverbank
  • protecting against erosion
  • removing silt

This is to make sure you do not interfere with our flood risk management assets or harm the local environment, fisheries or wildlife.

You could be breaking the law if you start work without getting the permit you need.

Working on a main river

You need a flood risk activity permit, previously called flood defence consent, if you want to do work:

  • on or near a main river
  • on or near a flood defence structure
  • on or near a sea defence
  • in a flood plain

Find out if you need to apply for flood risk activity permit.

Working on an ordinary watercourses

You do not need a permit to work on an ordinary watercourse – usually small rivers, streams and ditches. But you should contact your local authority responsible to apply for an ordinary watercourse consent.

If the work you're planning is in an Internal Drainage District (IDD) you will need to apply for a land drainage consent.

Contact us if you're not sure if the watercourse is a main river, ordinary watercourse, or part of an Internal Drainage District.

Tidal watercourses

Find out if you need a marine licence before carrying out work on a watercourse that is affected by the tide. 

Planning permission

Contact your local authority to check if you need planning permission before starting any work.

Mills and weirs

A mill or weir are structures which can control river flows and levels. You will need an impoundment licence to dam a watercourse or build a weir.

Contact your risk management authority if you want to build a weir, sluice gate or other control structure, or if you would like to modify an existing structure.

Work affecting protected sites and species

You must apply for a licence if you’re doing any activity that affects a protected species or a protected site.

Discharging water

If you are going to make a discharge to surface water (for example a river, stream, estuary or the sea) or to groundwater (including via an infiltration system) then you may need to apply for an environmental permit to make that discharge.


If you are 13 or over, you need a valid rod licence to fish for salmon, trout, freshwater fish, smelt or eel in Wales. It is important to check what your rights are, because fishing rights can be sold or leased.

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