Areas with calcareous rocks often have hard water, which can cause mineral deposits in water meters, typically lime scale and calcium, that decrease their level of accuracy. The water department of Region Gotland was challenged by deposits of calcium, iron as well as sand in their mechanical water meters.
As a result of the deposits, the meters displayed incorrect water usage and would sometimes even stop working altogether.
“The problem is most severe for those of our customers who have their own wells, as we use the water usage as the basis for sewage service charges. We do however also have significant problems with deposits in areas where the water hardness is especially high,” explains Susanne Bjergegaard Pettersson, Head of Region Gotland’s water department.
Furthermore, water meters are required by Swedish law to be replaced every ten years, but because of the iron and calcareous deposits, the water department has had to change some of the mechanical meters after only three years.
They therefore expect that replacing the mechanical meters with ultrasonic meters from Kamstrup will generate considerable savings.
Accurate billing requires accurate meter reading
Based on, among other things, positive experiences from other water authorities, Region Gotland chose Kamstrup’s MULTICAL® 21 water meter. Kamstrup’s ultrasonic meters have no moving parts and are, therefore, not vulnerable to mineral deposition and wear and tear.
The vacuum seal prevents moisture and condensation from entering the meter which makes it suitable for placement in, for example, meter wells. Also, the MULTICAL® 21 water meter has an expected lifetime of up to 16 years.
Ultrasonic meters are more expensive than mechanical meters. However, the water department expects the investment to pay for itself as a result of the increased accuracy of the meter readings and the increased lifetime of the ultrasonic meters.
A number of the new meters have already been installed and are functioning well, so orders have been placed for many more. Most of them will be MULTICAL® 21 but a small number of flowIQ 3100
will be installed at larger consumers.
Additional savings are expected from the built-in leakage detection in the new meters. This enables Region Gotland’s water department to quickly locate and fix the leaks.
Considering that a leaking toilet can at worst result in about 400,000 litres of wasted water in one year, effective leak detection can save customers a considerable extra bill.