Highway drainage systems

Highway Drains are designed to:

  • remove surface water run-off from the highway to help keep roads safe and minimise problems
  • prevent damage and make roads last longer through effective drainage
  • minimise surface water from the highway affecting properties or land

Our highway drains are not usually designed to provide drainage for other areas outside of the highway boundary.


  • If you are concerned about flooding, make sure that you report flooding to the right people.
  • If a blocked drain or flooding on a road is causing you concern report it to us.
  • We don't look after public sewers or fresh water pipes. If sewerage or a water leak is causing a problem on the road or pavement you should report the fault to the appropriate water company.
  • Problems with land drainage, such as ordinary watercourses, should be reported to the Lead Local Flood Authority, Internal Drainage Board or Environment Agency depending on the risk management authority for the location.

How we look after our drains

We need take an asset management led approach to maintaining the over 250,000 highway drains across the county.  Our approach is set out below;

  • Yearly inspections and cleansing of roadside drains throughout our key routes that link towns and villages.
  • Twice yearly cleansing of roadside drains most vulnerable to flooding – which are identified using enquiry data from historic reports from the public.

Find out more about our approach for managing highway infrastructure.

If a drain is not on the planned programme, it is maintained in response to reports of flooding. Reported drains are then risk assessed for highway safety and internal property flooding.

We aim to carry out non-emergency drainage cleansing in 28 to 90 days, but during extreme weather or periods of high demand routine cleansing can take longer to attend.

If flooding from the highway is causing internal property flooding or making the highway impassable for users, then we will attend as an emergency within 2 hours where possible. During extreme events of flash flooding this is unfortunately not always practicable.

If any defects within the drainage system are identified during routine maintenance operations, the enquiry will be passed to one of our local Drainage Engineers for further assessment.

Park your car somewhere else if you see signs telling you that cleansing will take place. We can't clean the drains if your car is in the way.

Don't tip waste such as concrete and oil down the drains as this can block the pipes and contaminate nearby streams, rivers and land.

Remove fallen leaves covering gully grills if you can do this safely. When doing this:

  • wear gloves if you are clearing leaves by hand.
  • put leaves in your normal rubbish bin or in a compost bin.
  • be careful not to step into traffic on the road and be aware of pedestrians.
  • don't lift the drain covers or put your hands into the drain as there might be sharp objects you cannot see.

To repair or improve our drainage systems, our engineers' work includes:

  • investigation work
  • minor works
  • broken pipe repairs
  • installing and enhancing drainage systems.

Our team of local Drainage Engineers can carry out specialist work such as CCTV investigations and root cutting in order identify defects and remedy them with the appropriate repairs.

If flooding keeps happening in the same place, we will investigate how the situation can be improved and these sites will be entered onto a forward programme of planned work.

These works are prioritised according to the risk to highway safety and risk to internal property flooding.

Other parts of our drainage system

We look also look after ponds, lagoons, pumping stations and soakaways which drain water from the road.

Ditches and grips

Ditches are generally the responsibility of landowners, although these ditches may take highway surface water. If a ditch needs maintenance works we can request landowners to do the required work.

Find out more about  owner responsibility for rivers and ditches

Ponds and lagoons

Some highway drainage systems drain to roadside ponds and lagoons. These are inspected and maintained in response to reports of flooding.

Pumping stations

We own 15 highway pumping stations. These are serviced every 12 months with additional maintenance done if needed.


Soakaways are large underground tanks. Water drains from roadside drains, through pipes and into these chambers where it gradually soaks into the ground. If cleaning roadside drains doesn’t clear the flooding, we investigate if nearby soakaways may also need cleansing.