No 'new maths' used by NWC

Letters to the Editor

No 'new maths' used by NWC

Friday, June 26, 2020

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Dear Editor,

We wish to respond to a letter to the editor published on Wednesday, June 17, 2020, with the headline 'New maths by the NWC'.

The central issue, we believe, surrounds the writer receiving two consecutive months of estimated readings, which resulted in a recalculation of the estimates after a subsequent meter reading was taken. For clarity, the billing of water used, where an estimation was previously done, is not simply cumulating those consumptions. The factors surrounding billing for water must consider two key variables — the number of days of service between billing (the billing period) and, more importantly, a tiered rate structure for billing for water consumed. Currently, there are four rate tiers for billing for domestic water as the rate that is charged increases with increasing consumption.

The recalculation of estimates is an adjustment done based on actual consumption and actual days of service, where an account was previously estimated. Whenever an estimated consumption is applied to generate a customer's bill, the actual reading, which follows, provides a calculation of the true consumption between the last actual reading and the current reading. This consumption may result in a debit or credit charge on the next bill.

The account in question was estimated at 27,000 and 33,000 litres or (27m3 and 33m3) for March and April 2020 respectively. A reading of 3861 was retrieved on May 22, 2020, which resulted in total consumption of 137,000 litres (137m3) for the period March to May 2020, 92 days.

The consumption of 137,000 litres was apportioned for the period based on days of service or, in other words, the days between billing, as follows: February/March, (29 days), March/April, (31 days) and April/May (32 days). The consumption of 137m3 was redistributed over the three periods as 43m3, 46m3 and 48m3 respectively. Therefore, additional consumptions of 16,000 and 13,000 litres were applied to March and April 2020 respectively, since the consumptions for those periods were underestimated. The consumption of 48,000 litres was calculated and applied for the May 2020 billing period.

Therefore, the consumption of 77,000 litres presented on the customer's May 2020 bill statement is a combination of the current consumption of 48,000 and the additional volumes after the recalculation of estimated consumption for both March and April of 13,000 and 16,000 litres.

Computing the May bill based on the difference in consumption of the May reading and previously estimated bills would see the 77,000 litres being billed over multiple tiers resulting in at least 36,000 litres of the consumption billed at tier 4 or $360.34 per thousand litres. However, this is against the apportionment of the consumption over three periods, where only 2,000 litres, 5000 litres and 7,000 litres were billed at tier 4 for March, April, and May, respectively.

With the use of the billed days and the apportionment of the actual consumption (the difference between the two actual readings) the customer benefited, as the charges billed totalled $21,119.91 as against $25,346.28.

The approach is not new maths, but a process established to ensure our customers are accurately billed. It also ensures that the customers receive the full benefit of the tier rate structure in place.

Notwithstanding this response, we had made contact with the customer; however, we are yet to be afforded the opportunity to help him understand the process involved in determining the final charges on a bill.

National Water Commission

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