Calculate your Bill
BWA’s bills for domestic customers are calculated according to four rates blocs and the charges are determined over a 30-day period. The rate blocs are as follows:
- $2.48 per m3 (0-8 m3);
- $3.10 per m3 (9-20 m3);
- $4.66 per m3 (21-40 m3) and
- $7.78 per m3 (over 40 m3).
If the customer used the water in a 30-day billing period then either the minimum charge or the rate blocs apply to determine the overall charge. The daily average formula may also be used.
Minimum Charge
e.g. 1
Meter reading indicates usage is 9 m3 in 30 days, this falls within the minimum amount (less than 12 m3) for which the minimum charge of $32 is applied.
[384 ($32 x 12 months) ÷ 365 (days) x 30 (days) = $31.56]
e.g. 2
Meter reading indicates usage is 8 m3 in 35 days, this falls within the minimum amount (less than 12 m3) for which the minimum charge is applied. However, since the number of days exceeds 30, then the overall charge is calculated using the daily average formula. [384 ÷ 365 x 35 = $36.82]
So for using 8 m3, the minimum charge does apply but must be prorated as the number of bill days exceeds 30.
Rate Blocs
e.g. 3
Meter reading indicates usage is 21 m3 in 30 days –
the first 8 are billed @ 2.48 = 19.84
the next 12 @ 3.10 = 37.20
the final 1 @ 4.66 = 4.66
Charge = $ 61.70
If the timeframe in which the meter is read exceeds or is less than 30 days then the amount is prorated over the actual number of days between meter readings.
The formula for calculating a bill for a period other than 30 days is done on a daily average and worked out as follows:
8 ÷ 30 × number of days in billing period = # of m³ to be billed @ 2.48
12 ÷ 30 × number of days in billing period = # of m³ to be billed @ 3.10
20 ÷ 30 × number of days in billing period = # of m³ to be billed @ 4.66
Remaining m³ calculated to be billed @ 7.78
NB: All blocs may not be used.
Example 1
Customer A used 46m³ in a 35-day billing period
8 ÷ 30×35 = 9.33m³ @ 2.48 = 23.14
12 ÷ 30×35 = 14.00m³ @ 3.10 = 43.40
46 – 23.33 = 22.67m³ @ 4.66 = 105.64
Charge = $ 172.18
Example 2
Customer B used 46m³ in a 31-day billing period
8 ÷ 30×31 = 8.27m³ @ 2.48 = 20.51
12 ÷ 30×31 = 12.40m³ @ 3.10 = 38.44
20 ÷ 30×31 = 20.67m³ @ 4.66 = 96.32
46 – 41.34 = 4.66m³ @ 7.78 = 36.25
Charge = $191.52
Example 3
Customer C used 46m³ in a 28-day billing period
8 ÷ 30×28 = 7.47m³ @ 2.48 = 18.53
12 ÷ 30×28 = 11.2m³ @ 3.10 = 34.72
20 ÷ 30×28 = 18.67m³ @ 4.66 = 87.00
46 – 37.34 = 8.66m³ @ 7.78 = 67.37
Charge = $207.62
Example 4
Calculation for usage of 120m³ over a 60-day billing period as compared with two (2) bills generated for usage of 60m³ over a 30-day billing period each.
8m³ × 2.48 = 19.84
12m³ × 3.10 = 37.20
20m³ × 4.66 = 93.20
60 – 40 = 20m³ × 7.78 = 155.60
Charge =$305.84
Charge for one month = $305.84
Charge for two months = $611.68 ($305.84 x 2)
8 ÷ 30 × 60 = 16m³ @ $2.48 = 39.68
12 ÷ 30 × 60 = 24m³ @ $3.10 = 74.40
20 ÷ 30 × 60 = 40m³ @ $4.66 = 186.40
120 – 80 = 40m³ @ 7.78 = 311.20
Charge = $611.68
Please note in example 4 that whether billed separately or together using BWA’s formula the charge is the same.
Sewage Tariff
Remember if as a domestic customer you are connected to one of the island’s two sewage treatment plants, a sewage tariff of 1/3 of the water bill is charged to your account monthly.
Commercial Customers
BWA’s bills for commercial customers are calculated according to the commercial rate of $4.66 per m3 and the charges worked out for the entire billing period in question.
Example
Meter reading indicates usage is 31 m3 in 34 days.
[31 x 4.66 = $144.46]
Sewage Tariff
Remember if as a commercial customer you are connected to one of the island’s two sewage treatment plants, a sewage tariff of 2/3 of the water bill is charged to your account monthly.
Estimated Bills
Estimated bills are calculated by the system using the same rate blocs regardless of the number of days - they are not prorated. Once the meter is read in the following month or months, the system goes back to the last meter reading and makes the calculation accordingly. Any payments that were made during this period are then subtracted from the total and the remaining balance charged to the account.
The criteria used by the system to calculate estimated charges are as follows:
- The previous month’s reading once there was one reflecting consumption OR
- The same month of the previous year OR
- The highest recorded usage in the period referred to as winter or summer peak.
- If none of the above criteria can be applied to the account, then the system uses the BWA generated average usage per household of 14 m3.
Customers whose meters are read in Imperial Gallons
There are still a few customers whose meters are read in Imperial Gallons (Imp gal.) and NOT in cubic meters (cu 3). The calculation of bills for these customers is different from the methods stated above.
The bills for these accounts are usually calculated in thousands of gallons while the water rates are stated in cubic metres, therefore the rates at which said bills are calculated will be different from those previously stated.
To calculate the rates used in these instances a converter is first worked out by dividing 1,000 gallons (each unit) by 220 gallons ( 1 cu 3) = 4.545454 This figure is then used as the multiplier on the four rate blocs
- $2.48 per m3 (0-8 m3);
- $3.10 per m3 (9-20 m3);
- $4.66 per m3 (21-40 m3) and
- $7.78 per m3 (over 40 m3)
which for the purposes of calculating these types of bills, then become
- $11.27272 per unit (0-8 m3);
- $14.09090 per unit (9-20 m3);
- $21.18181 per unit (21-40 m3) and
- $35.3636 per unit (over 40 m3).
Example
Customer A used 8 Imp gal in a 29-day billing period
8 ÷ 30×29 ÷ 4.545454 = 1.70 units @ 11.27272 = 19.17
12 ÷ 30×29 ÷ 4.545454 = 2.55 units @ 14.09090 = 35.93
8 – 4.25 = 3.75 units @ 21.18181 = 79.43
Charge = $ 134.53
Any customers who require in depth explanation of their bills are advised to call or come to the Barbados Water Authority’s Customer Service Centre for such.
Information compiled by the BWA’s Marketing/Communications Department
