The illegal practice of channelling rainwater from the roof to the street instead of into purpose-built wells is rampant in newly-constructed dwellings.

Just before the end-of-summer rains were due to fall and relieve the thirsty land, a water bowser carrying non-potable ground water came rumbling down the road.

The bowser made a stop to fill the empty wells of two houses in the street. A third house-owner looked on bemused. He had just replenished his own dried-out cistern with collected rainwater – stored over the previous winter – in long, low plastic tanks hidden under a raised garden terrace.

Each winter, when the gardens turn green once more following a series of cloudbursts, domestic wells are filled in a relatively short time, depending on the surface collection area of the rooftop. Rainfall usually peaks in October to December, falling off over successive months until summer.

Once full, any further rainwater channelled into the well goes to waste as it runs out into the street by means of the overflow pipe. This situation aggravates flooding in the streets while throwing away a precious resource.

Much can be done to improve efficiency and save on our excessive water consumption

As soon as wells are almost full to overflowing, the contents can be pumped into holding tanks to be kept for future topping-up, once the well runs dry again during the hot summer months. Rainwater storage tanks come in many shapes, styles and sizes, making them easy to incorporate into an existing garden.

In a good year for rainfall, a roof area of 100 square metres feeding a 20 cubic metre capacity cistern can be expected to meet most second-class water requirements of a normal household. (Claudine Cassar 2006)

Over the span of a whole year, collected rainwater could serve a household’s needs for toilet flushing, washing machines, water for washing floors and watering of plants, until the next year’s rainfall.

At the beginning of summer, a national workshop was held as part of an EU project on sustainable domestic water use in Mediterranean regions (SWMED). The aim of the regional project was to reduce the amount of ground water taken from aquifers by optimising the water needs of each person through water-saving devices, reuse of treated wastewater, rainwater harvesting, storage and use.

At the workshop, initial results of a local water audit revealed that much can be done to improve efficiency and save on our excessive water consumption.

The audit, conducted by water expert Marco Cremona on water consumption habits in typical Maltese homes is now nearly completed as analysis is ongoing.

Setting out to assess water consumption patterns, the audit has provided a useful breakdown of how water is consumed in Maltese households. The study is expected to identify which water-saving devices might work best in the home. Attitudes of domestic users toward water saving were also being looked at.

The exercise covers 32 homes in Attard, Birkirkara, Gudja, Mosta, St Paul’s Bay, Valletta and Żejtun and three households in Qala. Results for over half the homes involved in the survey were presented at the SWMED workshop held in Malta last May.

The aim of the audit was to assess water consumption patterns and provide a breakdown of how water is consumed in Maltese households. The study is expected to show which water-saving devices might work best in the home.

Water flow in taps and showers and toilet cistern capacities were measured. How often showers were taken and the use of toilets, pressure pumps and rainwater cisterns were all noted.

More than half of the 18 households surveyed up until May collected rainwater in wells or tanks but only four of these used rainwater for purposes other than gardening. Excluding these four, a third of homes consumed more than 90 litres per resident each day.

This exceeds the upper limit for the subsidised quota, after which a higher tariff is applied to metered water. On average the quota subsidy limit was exceeded by 24 litres per household, making the potential for savings even more attractive.

Many of the householders interviewed were not aware that taking a shower makes the highest demand on their household’s water supply. The study showed that showering or bathing made up an average one-third of consumption for the homes tested. This was followed by water used for toilet flushing, washing machines and water used at the kitchen sink.

Most sink faucets were found to be single lever with an average flow rate of over six litres per minute. Significant water savings can be achieved by fitting flow restrictors to kitchen taps.

Most respondents said they would be happy to install a water restrictor on their kitchen tap even if it meant that filling up a kitchen pot would take longer. They would not mind removing it for cleaning twice a year, reasoning that the savings far outweigh this small inconvenience.

A majority of householders questioned said they would be willing to spend up to €200 more for a water-efficient washing machine to gain long-term savings. The most popular water-saving measure turned out to be reducing the amount of water used in toilets. Apart from this simple measure, which can be supplied in kit form with simple instructions, some said they would be ready to spend a little extra for a dual flush toilet.

The average length of a shower was nearly six minutes, although the big wasters spent twice that time in the shower. Water-efficient shower heads could help cut down on water used for bathing.

Cremona pointed out that a mere 32 samples cannot be taken as representative of 150,000 households. “However, we have managed to get a pretty good idea where to focus to get maximum savings at minimum cost.”

Government distribution of free kits with water-saving devices is hopefully not too far off for householders willing to give it a try while saving on their water bills.

For water coming into direct contact with people, as in showers and wash hand basins, first-class water that is potable (drinking water) is usually the preferred choice. However, at least one demonstration household in Malta has for some years been using a combination of collected rainwater and recycled (grey) water for with dramatic savings on the water bill.

Cremona’s 500-year-old town house in Mosta was self-sufficient in water use for two people for a number of years. Even today, with double the number of inhabitants, the family still consume less than a third compared to the water consumption of a typical four-person household.