Site area charging
What is site area charging?
Site area charging is the method that we use to calculate the surface water and highways drainage charges for business (and other non-household) premises based in the North West where those premises are supplied through a water meter.
This involves measuring the total area of a premises including the boundary and all land within the boundary. We then exclude any permanently grassed, cultivated or landscaped areas where no surface water or ground water drains into a public sewer.
If the water supply to the premises is not via a meter (an unmeasured supply) then the surface water and highways drainage charges are calculated based on the rateable value of the premises. The exception to this are individually rated car parks which are also charged based on site area.
Surface water charges cover the removal and treatment of rainwater from a site or premises, for example water that drains into the public sewer from the roof, car parks or other hard standing areas.
Highway drainage charges cover the cost to remove and treat rainwater falling on the roads and footpaths in our region. Everyone connected to the public sewer must pay for this part of the sewerage service.
Can I claim a reduction in my surface water charges?
If all or part (more than 10%) of your surface water does not drain to our sewer, either directly or indirectly, you may be eligible for a reduction to your surface water charges. If you think this applies to you then please contact your retailer to discuss this further. Claiming a reduction in your surface water charge will not reduce your highway drainage charge.
Can I view my site area plan online?
For most sites we provide an online map checking service where you can view the site area plan for your site.
Please note that you should first read and accept our terms and conditions governing usage of our map checking service. You can then log in by clicking here.
To access the service you will need to have available your Wastewater Service Point Identifier or SPID (starts with a ‘3’ and is 13 characters in length) and the property postcode. If this information is not shown on your bill then your retailer should be able to provide this for you.
Once you have logged in, the map will automatically show your premises location providing we know where your premises is located. If you think the plan is incorrect or there are any errors with either our data or the Ordnance Survey data, please discuss this with your retailer.
How we measure the chargeable area of a premises
The size of a chargeable area determines the wholesale charges related to surface water drainage and highway drainage services. You can see our wholesale site area charge bands in our current year wholesale sewerage charges scheme found here.
To determine a chargeable area, we measure the total area of the premises including the boundary and all land within the boundary, and then exclude any permanently grassed, cultivated or landscaped areas, where no surface water or ground water drains into a public sewer.
A site area charging band will be allocated to the premises based on the chargeable area, including the allocation of a proportionate part of any common areas. The proportionate part of the common areas will be assessed pro rata to the individual site measurement of each separate premises supplied by the supply point, or, if the floor area of the individual premises cannot be readily determined, pro rata to the individual charging value of each premises, as determined by us. For buildings in multiple occupation, common areas may include areas both internal and external to those buildings.
The three diagrams linked below show how we calculate a chargeable area, and how we use this measurement to allocate a wholesale site area charging band for the premises.