NI Water bill non-domestic customers in different ways depending on whether a water meter is fitted or not. NI Water provide an explanation of these billing methods on their website.

If there is anything you don’t understand about your bill then get in touch and request our free Water Bill Health Check. If you need to contact NI Water about your bill you can phone them on 0345 877 0030 or email them at

Measured Bills

The customer reference number on these bills starts with MC, it is helpful to have this number to hand if you phone NI Water. 

This billing method means that you pay a standing charge for your water service, similar to phone line rental, and then an additional amount for the water that you use. This is called a volume rate. If your waste water goes into the public sewer system then you also pay a sewerage standing charge and a volume rate.

Most customers receive two measured bills per year. If your bill straddles the 1st of April then your bill will have two sets of all these charges, this is because the annual Scheme of Charges is released that day.  The charges are split from before 1st April and from 1st April.

There are rules relating to VAT and allowances on a measured bill. Many customers are not claiming the allowances they are entitled to. We can help you claim these allowances if you request a free Water Bill Check.

Unmeasured Bills

The customer reference number on these bills starts with UC, it is helpful to have this number to hand if you phone NI Water. This billing method can either be fully unmeasured or based on an estimate of how much water you would use.

A fully unmeasured bill is based on the rateable Net Annual Valuation (NAV) of your property. Therefore the larger your NAV the larger your bill, irrespective of how much water you use. Unmeasured bills do have an upper limit charge cap. The current charge cap, until 31st March 2024, is £570 for water use and £615 for public sewer use. Customers receive one bill a year, usually in April or May.

The alternative method of billing a customer without a meter is called Assessed Charges.  With assessed charges you pay a standing charge, similar to a measured customer, and additionally you pay a variable charge based on an assessment of how much water your property would use. NI Water will only consider an application for assessed charges billing after they have surveyed your property to see if they can fit a meter. You need to contact NI Water and ask them to do this.

Trade Effluent Bills

Some customers receive an additional sewerage bill, know as a trade effluent bill. This type of billing occurs when it is not normal waste water that is being discharged to the public sewer.

Shared Supply Bills

If you are located in a building or an enclosed site that has more than one business or a mix of business premises and domestic homes then there may be cost effective methods of billing that are outside the responsibility of NI Water.

Additional allowances may also be available if other homes or businesses are sharing your metered water supply. You can get further information in relation to this by requesting our free Water Bill Check.