You are here: Home Publications RACA Journal

Water meters…what you need to know

E-mail Print PDF

watermeters1By: Lesego Malete

There are two purposes for metering, one is customer billing and secondly, it is vital tool for the management of water distribution and consumption.

“A domestic water meter, whether pre-paid or conventional, is a custody transfer device, a means of transferring a product from a supplier, the municipality, to the consumer or end user. Consumer water meters measure the volume of water from which the cost of purchase is generated,” says Basil Bold managing director of Sensus, a metering specialist company.

The fundamental difference between the two systems is, in the case of prepaid, the consumer has to pay cash for the water in advance whereas with the conventional system the consumer pays in arrears against an account. When purchasing prepaid water, the token is credited with the amount the consumer buys.

For Bold, the prepaid system is discriminatory. If you look at the prepaid system in this country, it’s found in low income areas. People living in Sandton have the privilege of paying at the end of the month, and the people who can least afford the water pay upfront. Prepaid is a technical solution for a social problem, which certainly offers an element of water demand management, but it needs to be questioned whether there are not simpler and more cost effective ways of achieving this goal?

According to Sean Wheller of Enbaya PrePaid Meters, prepayment technology was developed in South Africa in the late 80’s. “Prepayment systems became popular in the 90’s, not only in South Africa but also in countries like the United Kingdom (UK), India,  Argentina and others.” He adds, “Water meters have been around for a long time, however, implementation has been difficult in South Africa due to constitutional issues which have been resolved.”

The conventional Route
In South Africa the conventional system relies on water meters installed on property boundaries which are ideally read monthly and from which a municipal bill is generated. Difficulties with the system are the frequency and reliability of meter reading, problems with rendering accounts and the reluctance or inability of consumers to pay.

While it is recognised that South Africa is water stressed, it is ironic that relative to European or American standards water in this country is an extremely cheap commodity. As a result the average consumer has no idea of their monthly consumption and pays little regard to using water wisely. While prepaid systems can contribute to better water usage, Bold believes that modern technology such as so called electronic “smart metering” and Automated Meter Reading (AMR) can be applied to educate consumers on their water usage.

Electronic and Mechanical
According to the manufacturers currently the overwhelming majority of all conventional meters are mechanical. The primary reason being the high capital outlay for modern electronic technology.

watermeters2Some of the larger meter manufacturer’s have smart metering technologies available but the economics don’t add up for domestic consumer metering at present. However as the price of water increases and the numbers of smart metering devices sold increase with a commensurate decrease in cost, it will not be long before smart metering technologies become viable says Bold.

With respect to existing domestic mechanical meters there are two widely used technologies:

• The inferential or the turbine meter, which measurement system is to spin the turbine or rotor that comes up to a register and counts.
• The piston meter, on the other hand, works on a different principle where the water comes in at the bottom and gets trapped in the measuring chamber. As the piston moves around, it discharges the water out on the other side. This is a positive displacement as it takes out the exact volume and takes the water through the meter.
Elster Kent Metering’s volumetric water meter range has been used in the domestic market for a number of years. The company says due to the volumetric rotary piston measurement principle, its V100T range can achieve the highest levels of reading accuracy even at the lowest flow rate.
The meter can be installed in any position without affecting its accuracy. The non-return valve provides protection against outside interference and prevents the meter from being operated in reverse direction.

Mogale City municipality is one of the municipalities utilising prepaid meters and Hennie Gouws, manager of conventional meters in the water network department, says the battery life of prepaid lasts up to five years and thereafter, it has to be replaced.

The Sensus’ Smart meter has an open pipe and uses an electronic principle for measurements. The advantage of this meter, according to Bold, is it has no moving parts and the battery life lasts up to 20 years. However, the disadvantage regarding this meter it is expensive, costing at least R800, whereas the conventional meters cost up to R150.

Battery failure
The battery life of these meters poses some concerns. When the battery fails, the whole meter is taken out if the battery cannot be replaced. With the new prepaid water meters, the manufacturers allow for the batteries to be taken out, in case they need to be replaced. Prior to this, the whole system was replaces due to failures. The problem lies with the municipality when the battery fails.

Plumbers are not installing the meters. Private companies employed by the municipalities install the meters whether it’s conventional or prepaid. These private companies in turn employ the community members and train them to install the meters. Mogale City municipality says they use the services of small medium and micro enterprises (SMMEs) to install the meters.

Enbaya PrePaid Meters suggest the services of trained specialists because these AMR meters need to be configured to the Advanced Metering Infrastructure (AMI) network.

watermeters3This draws one to the question of what happens when the water meters are installed incorrectly. The manufacturers admit that often times, the water meters are installed incorrectly posing problems while the municipality argues that the problems they experience are due to the manufacturing of the product. Keith Bailey, sales and marketing director of Elster Kent Metering Limited utters the same sentiments that failure with the meters is due to the installations.

Leon Basson, product manager for prepaid meters and AMR from Elster Kent says the company’s water meters have an arrow on the side of the product indicating the direction in which the meter should be installed. The prepaid meters have a non-return valve which shuts off the water when installed incorrectly. Another problem with installations is when the installer is working with sand and pipes while connecting a water meter box. If the pipes are not flushed, a handful of sand can enter into the water meter and cause blockages.

This is another controlled system. This limits the amount of water used per day. When the user reaches for example the 200 litres stipulated by the municipality, the valve will shut off the water supply until a set period. With this system, users are not billed for water; the municipality controls the amount given to each household.

Automated meter reading system
Water metering should be flexible and that’s created a demand for automated meter reading system which is a communication devices. These systems are connected to the meters. Elster Kent uses the radio modem, a GSM concentrator and a meter interface unit. The latter provides a link between the utility’s servers and the AMR meters. The radio modem has a radio frequency to allow for communication with all the meter interface units (MIU) within its range. The MIU can be fitted to most pulse meters with the external connection to the meter. This device includes a self- contained radio frequency transmitter/ receiver to use as a two way communication device.

Bailey says the need for prepaid water meters in South Africa is driven largely by the situation that local authorities find themselves with huge consumptions that the consumers cannot pay for as a result of leaking toilets and taps.

“With prepaid meters the advantage is that the consumer has control of the consumption and budget. This means that one can consume according to what one can afford,” says Wheller.

The disadvantage of this system, according to Wheller is the same as advantages, divided into two for the consumer and supplier, the municipality and utility company respectively. “For the consumer voluntary disconnection is a disadvantage. If one does not have money to buy water, they will be disconnected from the services until the free water allocation the following day.

From the municipality, the disadvantages can vary, but general market data suggests, that this could be financial or infrastructural. The municipality may not have the finances to implement such technologies or in some places the infrastructure may not support the technologies, an example could be the GSM network, says Wheller.

The challenges with prepaid water meters are the network. Wheller says: “South Africa is blessed with a relatively good infrastructure, while other countries have a serious problem with their GSM networks. This means that they can’t run data on the AMI network between the meter and the vending systems.

In turn it means that AMI is hard to implement or not possible because the meter connect to the payment system. The second challenge would be a financial. AMI/AMR meters are more expensive than Standard Transfer Specification (STS) meters, which puts water meters in a category less attractive to pursue.”

Bailey points out although prepaid water meters are expensive, water in South Africa is cheap. Users can purchase 1 000 litres of water for less than R4.00 and the community still get free 6 000 litres per month. He adds that many of the people on prepaid only use the free water they receive. “The leaks are criminal in this country in that we cannot afford the amount of water going down the drain and that’s creating a demand for prepaid.”

watermeters4Prepaid types
The choice for the municipality or utility company would depend on the infrastructure and vending which the meters perform to. A meter is nothing but a device, to perform prepayment the device has to be connected to a system that talks to the meter. The choice is usually in the vending system primarily and secondary the devices itself.

This means that one could choose a cheaper meter, and then one may compromise on the vending system, alternatively the opposite can also occur, says Wheller. Basson distinguishes the three types their company manufactures: the wall mounted domestic meterbox, above ground domestic meterbox and communal stand pipes. The wall mounted and above ground meters are designed for individual households.
With the wall mounted meter, the prepayment system is incorporated in the meter which is installed on the wall outside the house. Both the wall mounted and the above ground meters use an alkaline battery with a calculated life of up to five years. Elster Kent says these two meters have a one touch conversion to conventional meter back to prepaid meter feature.

The communal standpipe is designed for communal sites to control the prepaid quantities of water. Features on this product include zoning, where the consumer draws water at specific dispensers, it has a secure encrypted token, the LCD screen indicates to the consumer the amount of credit remaining and it has a tamper detection device. Depending on the amount of users, the meter’s battery life can last up to three years.

The Key to receiving water
The key to receiving water is using the token. Consumers can lock their meters with these tokens. Elster Kent has five different tokens for its prepaid system. The tokens are colour coded, the consumer uses the blue token, and the orange token belongs to the vendors who sell water. The green, red and the yellow token are used by the maintenance, management and the engineering people respectively. Water metering information is transferred through the token to the management system at municipalities.

Basson lets slip that there is a new project in the pipeline where prepaid stand pipe meters will be installed at taxi ranks. Users will have their own token to get the water they need to wash their taxis. Currently, taxi ranks are using free water.

Is Prepaid the new conventional
While the prepaid meter is fast becoming an option for many people, conventional meters cannot be written off just yet. Bailey says Elster Kent Metering still sells more conventional meters than prepaid.

New features on prepaid
The Elster Kent team tells Plumbing Africa that prepaid water meters have gone through changes throughout the lifeline of the meter. These are mostly software changes which have been implemented to incorporate features stipulated by the customers or the municipalities.

According to Basson and Bailey, reading the meter is not difficult. The monitor or screen indicates to the user how much water is available, both the free water and credited water. A totaliser, one of the features indicated how much water is flowing on the meter. With the water meter, the user receives a product manual and it has error codes to help users as the encounter problems with the meters.

The error code should noted when calling the call centre to report an error. While manufacturers used to produce brass water meters, both with prepaid and conventional, a new feature with the devices is the plastic water meters boxes. The error code should be noted when calling the call centre to report an error.

While manufacturers used to produce brass water meters, both with prepaid and conventional, a new feature with the devices is the plastic water meters boxes.
Conventional or prepaid? You decide!

Only registered users can write comments! | Register Here

3.26 Copyright (C) 2008 / Copyright (C) 2007 Alain Georgette / Copyright (C) 2006 Frantisek Hliva. All rights reserved."


HVAC&R Advertising

Please update your Flash Player to view content.


talk pic 

For Sales,
Editorial and Subscriptions:
Email: hvac&
Tel: 00 27 11 579 4940
Twitter: @hvacr_online
Facebook: HVACROnline

Search Directory

projects header

Simply send an email to hvac&

projects picOR click here for our project galleries ...


Click here for our latest technicals & features!

raca  coldchain


Plumbing Newsletter
HVAC&R Newsletter
Mining Newsletter
FIRE Newsletter

Receive HTML?

RACA Events

There are no upcoming events currently scheduled.
View full calendar

Latest Poll

Do you find the IMD website useful?

Contact Details

Head Office:
13A Riley Road, Bedfordview
2007, South Africa   

Tel: (011) 579 4940
Fax: (011) 450 1920
International: 0027 (0)11 579 4940