Each water company will prepare its bills in a different way. However, there are a number of common elements which will allow you to understand how you are charged for water. Depending on the water and sewerage companies you may receive separate bills for water and sewerage, or you may receive a single bill covering both.
Elements of water bills
All non-domestic customers with a water meter pay a standing charge, based on the size of the meter - this is the charge applied for giving the business access to water (not for the water itself).
Metered water charge
This charge is for the water used and is based on the measured volume of water supplied to the business through the meter.
Businesses that do not have a meter, may be charged based on assessment by the water company, or charges will be based on the rateable value of the property.
If you believe that your business should be metered, or you are being billed incorrectly contact your water company.
Elements of sewerage bills
Sewerage charges cover foul sewerage and drainage, and are usually linked to the volume of water used. These charges are normally related to the volume recorded on the water meter with an allowance as some water will not return to the sewer. Standing charges are added and are fixed according to the size of the meter.
The drainage charge is split into:
- surface water drainage (run-off from rainfall onto buildings)
- highway drainage (run-off from roads and highways)
Sewerage Cost Calculations
Sewerage (domestic wastewater) charges appear on either your water bill or your trade effluent bill and can be calculated in one of the following ways:
- incoming water minus non-return to sewer allowance
- incoming water minus measured trade effluent volume minus non-return to sewer allowance
- the number of people on site
- the rateable value of your premises
Trade effluent bills
Trade effluent is liquid waste which is produced wholly or partly in the course of any trade or industry carried on at trade premises. (It does not include liquid covered by normal sewerage charges). The charges cover the costs of removing substances from the water.
Trade effluent includes waste water contaminated with:
- food waste
- fats, oils and greases
- heavy metal rinses
Water companies charge according to the volume and strength of effluent before it is discharged into the sewers. If your premises are connected directly to the sewage treatment works it may be possible to reduce the charge.
Before discharging effluent into public sewers a business must have the consent of the water company. For more information contact your water company (in Oxfordshire this is Thames Water).
Trade effluent cost calculations
Trade effluent volume may be metered or can be based on the calculation of:
water use minus non-return to sewer allowances.
To help the water company calculate the volume discharged as domestic sewerage, you may be required to provide additional information.
Trade effluent charges are based on the 'Mogden Formula' that relates cost to the volume and strength of the trade effluent discharged. The formula takes into account the facilities at the sewage treatment works that treats your trade effluent. For more information see the Offwat Website .
All elements of a water bill can have VAT applied to them. You should ensure that VAT is charged at the correct rate.
General advice on understanding water bills
Costs for water vary across the UK. But you can check that your business is being billed correctly:
Serial number - check the serial number on your bill matches the When you receive a bill, check the meter serial number to make sure you are being billed for your meter.
Read your water meter - Bills can 'estimated', 'actual' or 'read' meter readings. Company water readings can be very occasional, so ensure that your bill is correct by reading your meter and where possible providing readings to the water company (or failing that keeping a record of readings will ensure that estimated readings are accurate, and allow you to challenge readings when they are not).