Impermeable Area Studies and Surface Charge Rebates

Water companies charge both domestic and commercial properties for the use of public surface water provisions. This fee can be applied in a number of different ways but is largely based upon the total area of your property. This should usually only apply to impermeable areas such as car parks or roofs from which rain water will drain directly into surface water pipes; however commonly water companies have not correctly calculated this meaning that you could be charged additional for permeable areas such as grass.

The problem

Water companies work out the amount you will be charged for surface water drainage; however it is your responsibility as a consumer to ensure that you are in fact paying the correct amount. Due to limited resources as well as a natural inertia on the subject, water companies have rarely spent a great deal of time or expertise on reappraising these over time.

In some cases changing from one band to another can result in saving tens of thousands of pounds a year.

The solution

EDS has the expertise and experience to be able to effectively advise you on whether you’re paying the right amount for surface water drainage or whether you could be entitled to a reduction and rebate.

For an initial assessment for commercial and public sector locations, all that we require are details of your property boundaries and a copy of your bill for surface water. From this we can make a reasonable judgement about how likely you are to be able to get a reduction.

Often simple, quick, and cheap changes such as redirecting surface water lines from your property directly into local water courses or using sustainable drainage systems to redirect it into permeable areas can be all the changes you need to make in order to save money every year.

Sustainable Drainage Systems (SuDS)

Sustainable drainage systems can take a lot of different forms. In principle it’s about using natural drainage processes to replace reliance on surface water lines. In urban areas this might include the permeable pavements or green borders along roads, while it can also be used to treat industrial effluent using a combination of shale and reed beds to purify water. For the purposes of reducing reliance on surface water systems for commercial and public sector businesses SuDS are usually limited to a number of basic, common sense approaches designed to let surface water drain away naturally without causing waterlogging or interfering with day to day operations.

The savings and benefits

Significant savings can be gained yearly from reassessing your chargeable area. Moving from band seven to band six for example (band 15 being the highest and band one the lowest) can save you nearly £5000 per year with some water companies. In addition to this if the initial banding was incorrect, for example if it was assumed that your total area was impermeable then you have the potential to have the difference for up to 10 years previously rebated.


Having worked alongside water companies for over 35 years we understand how these decisions are made. Our experienced team can make the right assessments and suggest the right actions to take to save you money year on year.

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