In coming years water companies will need to tackle “difficult cases” for metering if they are to meet their metering projections. Current penetration is around 40 per cent of homes, and water companies are allowing for that to increase during AMP6, such that around 57 per cent of homes will be metered by 2020. Ofwat, in its 2011 report on the costs and benefits of metering, expressed an ambitious desire that meter penetration should reach 90 per cent by 2030.
One group of properties where metering has typically been difficult comprises multi-occupancy buildings, such as flats and apartments. These are often bulk metered, where there is a meter on the main supply but charges to individual tenants are allocated by the landlord or building management company. The benefits of this approach for the water company include there being only one bill payer, and that losses within the internal supply are captured in the meter read. However, disadvantages include the distant or absent nature of any relationship between water supplier and end-user, and between the end-user and their water consumption, together with uncertainty on individual consumption and night flows. Debts from failed management companies can also be large and difficult to recover.
Water companies in the UK have been reluctant to meter individual flats, or sub-meter, although it is common in Europe and increasing in the US and Australia. In the UK, it has been argued, customers living in flats have less discretionary water use, primarily because of the lower levels of garden watering, and therefore the water savings on offer are correspondingly lower.
However, a study in the US (Meher et al, 2004) showed that demand reductions averaging around 15 per cent were achievable by sub-metering because of the savings arising from better identification of losses and greater awareness of water use by individual consumers.
In some parts of Europe, such as Denmark, it is compulsory to meter individual flats, and in places it is required to have sub-meters and a bulk meter to capture common use and internal supply losses. Waterwise in a 2007 report on sub-metering did not rule it out, but concluded that metering whole buildings should be the priority – and that sub-metering could then follow. Certainly, if metering penetrations anywhere near Ofwat’s ambition are to be achieved, sub-metering will be needed.
With most water companies now adopting radio-read meters, the age old problem of getting access for meter reading has been overcome. However, flats present other challenges that can make metering expensive. For example, many apartment buildings have multiple risers, meaning there may be more than one entry point for water into an individual apartment, and thus more than one meter may be required for each. In addition, plumbing layouts can be complex and it is not always clear where the stop taps are. Ideally what is needed is a novel method of metering that is low cost – so multiple units are not an issue – and both non-disruptive and quick to install.
Although such a unit does not yet exist on the market, WRc in conjunction with a group of water companies has developed an aspirational specification for such a device. Because the biggest component in the cost of installing a conventional meter is the labour, one alternative approach we have been exploring is quick and less disruptive ways of installing conventional meters. This might provide a solution while meter technologies develops.
The final hurdle that will need to be overcome is regulation. A framework for applying the various regulations on metering to the sub-metering situation is required such that the rights and responsibilities of all parties concerned are clearly defined and understood. The relationship between tenant, landlord and water company can be complex, and the switch from bulk metering to sub metering will have its issues.
Overcoming these issues now will allow companies to put in place sub-metering alongside conventional metering as there is a move to full-scale household water metering. Andy Godley, senior consultant, WRc plc