Drainage and flooding on the highway



Floods can occur during prolonged rainfall and after flash storms. The Environment Agency issues warnings when river and tide conditions are such that there is a risk of flooding. 

Cornwall Fire and Rescue service provide detailed information on preparing for and dealing with flooding of properties.

Report flooding on the highway

For all non urgent problems, such as blocked gullies and drains, small areas of standing water or water flowing onto the highway from adjoining land:

Report flooding on the highway

To report urgent problems where there are large areas of standing water or the road is impassable and is causing a safety hazard or water from the highway is flooding adjacent property, please telephone 0300 1234 222 (24 hour service) giving details of the location. In extreme weather conditions with heavy rainfall, work will be prioritised according to severity and availability of resource.

Please note - drains and pipes carrying sewage are the responsibility of the water authority and problems should be reported direct to them on 0800 230 0561. Calls to this number are free from landline phones, however, mobiles charges may apply.


Please read our Sandbags procedure which explains the use of sandbags in emergency situatons.

Highway Drainage Maintenance

CORMAC looks after the county’s highway drainage systems, on behalf of Cornwall Council.

Highway drainage systems are designed to:

  • Remove surface water from the road to maintain road safety and minimise nuisance
  • Provide effective sub-surface drainage to prevent damage to the structural integrity of the highway and maximise its lifespan
  • Minimise the impact of highway surface water on the surrounding environment

Highway drainage systems are not designed to:

  • Remove surface water from adjacent land or properties
  • Provide an overflow system for land drains, watercourses, rivers or sewers

We carry out planned and reactive maintenance not just to highway drains, but also to those leats and other waterways for which we are responsible. 

Planned highway drainage maintenance takes the form of regular scheduled visits to carry out operations such as gully emptying, ditch clearance and maintenance of grips and boltholes. 

We empty gullies at frequencies varying from six months to two years depending on the location of the gully and the importance of the road. 

We deal with ditches, grips and boltholes as part of our regular maintenance of the rural network. We also maintain other drainage assets including leats, soakaways, ponds and culverts.

An important part of our role is to inspect and treat flooding “hot spots” when we receive a forecast of very heavy rain.  This is particularly a problem in the autumn when trees are shedding their leaves. This reactive maintenance typically involves us checking that all of the road gullies in hot spot locations are operating and that trash screens on watercourses for which we are responsible are clear of debris.

How can you help

If fallen leaves are covering the gully grids and you can safely remove them then please do. These can be disposed of, if necessary, in your normal rubbish bin or in a compost bin.

When removing leaves from drains, be careful not to step into traffic on the road and be aware of pedestrians on pavements. 

Don’t lift the drain covers or put your hands into the drain as there may be sharp objects you cannot see. Wearing gloves is always a good idea if you are clearing leaves by hand.

If blocked drains are posing a risk to safety or affecting residents’ homes and you are unable clear them, please report them using the link above. Please give us as much detail as you can about the location of the drains and the impact they are having on safety, property and the local community.