Watercourses – Common Law rights and riparian responsibilities

You are known as a ‘Riparian Owner’ if you have a watercourse, ditch, stream, river or culvert within or adjacent to your property boundary.  In some cases, a watercourse may be unowned in which case the adjacent owners are responsible up to the centre line. You can check your deeds for your property if you are not clear about ownership.  

As a riparian owner, you have the responsibility to maintain the flow of water through or adjacent to your property. These are set out in the Public Health Act 1936, the Land Drainage Acts of 1991 & 1994 (as amended by the Flood & Water Management Act 2010), the Water Resources Act 1991. We as a council have our own local land drainage byelaws.

We work on behalf of West Sussex County Council (the Lead Local Flood Authority) to identify where watercourses in this District and Chichester District have become obstructed and inform and advise riparian owners of this and if necessary, carry out enforcement of riparian responsibilities.  

For more information, please see our rights and responsibilities of living by a watercourse website page and relevant West Sussex County Council and EA produced documents. 

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.

However, the common law right to natural drainage means that, legally, 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.  It also means that lower landowners should not take any action to prevent such natural flows entering their land.  However, there is also 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 is likely to 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). 

If run-off from higher ground is causing problems on your 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 council 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, or a breach of the Land Drainage Act 1991.