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Your bill and our charges

Understanding your bill

Both metered and unmeasured (unmetered) customer bills have a standing charge element. This standing charge is a fixed charge which includes the cost of providing a water supply.

For Measured (Metered) Customers the standing charge element is based on the size of the supply pipe to your property. For Unmeasured customers the standing charge element is a fixed rate.

More details of charge bands can be found in:

Your Bill Explained

Your bill will be based on the particular services you receive from us, how much water you use as a metered customer or the rateable value of your property if you are unmetered. 

  • Your unmetered water bill explained. PDF

  • Your metered water bill explained. PDF

  • Your Trade Effluent water bill explained. PDF


Measured (Metered Customer Information)

If you have a meter fitted the volumetric element of your bill will be based on the readings from it. The volumetric charge is calculated by multiplying your water use in cubic metres for the billing period by the price per cubic metre. Meters are normally read on a 6 monthly frequency and bills are issued accordingly. Bills are based on the actual usage shown on the meter. If a reading is not available, the usage will be estimated based on previous consumption.

To help with early leak detection we recommend that you take regular readings as you are liable to pay for all water registered through the meter. A significant increase in your consumption may indicate leakage on your supply.

Customers receiving an estimated bill may read their meters, where it is practical to do so, and let us know the actual consumption within 7 days, by telephoning our Billing line on 0345 877 0030. This meter reading will also be used to calculate the charges for the disposal and treatment of your waste water. A new bill will be issued to you based on the reading you provide.

Charges are also incurred for the disposal and treatment of waste water.

These Sewerage charges will also be included on your bill. This is dependent on the Sewerage services provided.

The sewerage element is also be made up of 2 parts:

  • A standing charge – which is fixed and based on your water supply pipe size
  • A variable charge – which is based on the water you use. To do this we assume that 95% of the water we supply is returned to the sewerage system.


Unmeasured (Unmetered) Customer Information

For customers that do not have a meter fitted the bill is calculated based on the rateable Net Annual Value (NAV) of your property as assessed by Land and Property Services (LPS). Unmeasured customers are billed once a year, usually in April or May.


Assessed Charges

If we cannot fit a meter at your property, you can ask to be billed on assessed charges. Assessed charges take account of water using devices in your property instead of unmeasured charges, based on the NAV of your property.

Assessed charges are calculated by us and have two elements:

  • The full unmeasured standing charge; and
  • A variable charge based on an assessment of water consumption at the property using loading units.

Different water using devices have different load unit values.

We will send you an application form and will calculate your assessed charges based on the information you provide within 5 days.

We will send you a letter showing what your assessed charge would be and you can decide to accept or remain on unmeasured charges. If you pay business rates on your property then a rateable water and sewerage allowance may be available.


VAT Classification

Depending on the nature of the main non-domestic activity at premises served by NI Water, you may be liable for VAT against water charges. So that your VAT classification can be assessed and updated if required, print our VAT Classification Form, complete and return.

Charges for the reception, disposal and treatment of foul water, sewerage and trade effluent are zero-rated.


Allowances Available

There are 2 main allowances available to NI Water customers that may reduce bills. These are domestic allowance and leakage allowance:


Rateable Water and Sewerage Allowance

A rateable water and sewerage allowance may be available to measured customers paying business rates. This is subtracted from the volume recorded by the meter, before calculating the volumetric water and sewerage charges. Customer can apply for this allowance by contacting NIW. We may require proof of your rateable status to confirm eligibility.


Non Return to Sewer Allowance

For measured customers, sewerage charges are made up of two parts:
  • A standing charge based on the diameter of the supply pipe; and
  • A variable charge based on volume of water used (this volume is based on the water supplied, less a non-return to sewer allowance of 5%)

In certain circumstances more than 5% of water supplied may not return to the public sewer. If this is the case, you may be eligible for an increased allowance against the volumetric charge. An application pack is available, and will require you to provide accurate records to enable the calculation of any additional allowance. You may also be required to install additional meters to record water for certain activities where it is not returned to a sewer after use.


Leakage Allowance

Leakage Responsibilities, Allowances and Costs

Moving or Ceasing Trading

You are responsible for notifying us if you are moving premises or ceasing trading. Please tell us at least two working days before you leave or you will be liable for any charges up to the date of whichever happens first:

  • 28 days after you tell us;
  • The day when the meter would normally next be read; or
  • The day when someone else tells us that they are taking responsibility for the supply.

You should also phone us on the day you leave to provide a final reading. We will close your account on the basis of a meter reading you provide, or if you cannot do that, on the basis of an estimate if you agree.

Further guidance and information regarding Billing and Metering can be found in the document below, which can be printed for future reference.

Billing and Metering for Non Domestic Customers Code of Practice

Paying Your Bill

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