The benefits of a 1.6-gallon flush volume with a reduced flush (dual flush) for toilets, reduced flow showers and improved design of clothes and dish washing machines are being assessed through recent surveys performed in the U.K.

Issue: 3/02

In January 2002 the U.K. government released the 1901 census Web site. Despite crashing immediately due to the volume of interest, it has since been reinstated and is proving immensely popular. The surveys there provide a snapshot of what life was like and allow comparison with our own environment. Comparison with 1901 could induce a feeling of d? vu. Surface travel in London then as now averaged 4 miles per hour, although pollution took the form of tons of horse manure not carbon monoxide. The army was engaged in Afghanistan, and there was war in the Balkans. A robust American president was unafraid of overseas involvement, and Britain's ambivalent approach to Europe was summed up by the Times of London headline, "Fog in Channel, Europe Cut Off." However, the census will assist many to trace their forebears. It will provide comparison in areas where progress has been marked, e.g., health care and infant mortality. The site may also be of interest to many U.S. citizens whose forebears joined the migration to the U.S. in the first decade of the 20th century. The web site address is

While not having the same impact as the 1901 census, the recent publication of a 1999 survey titled, "Using Water in the Home in Scotland," by the three Scottish Water Authorities is an essential contribution to knowledge. It will allow the assessment of legislation aimed at reducing water consumption. The introduction of a 1.6-U.S. gallon w.c. flush volume with a reduced flush (dual flush) for urine removal, reduced flow showers and improved design of clothes and dish washing machines will be assessed when future surveys are compared to this authoritative research.

The study follows surveys in 1982 and 1991 aimed at a national assessment. The data covers overall water usage figures and the purposes for which water was used throughout the day. The objective was to assist infrastructure planning and the identification of a basis for service charges. Forty-eight zones across Scotland included 10,500 dwellings. The study involved flow measurement, data analysis, household interview surveys and self-completed one week diaries. Data sampling included 5-minute and 12-second interval collection.

The median domestic per capita consumption (PCC) was 37 U.S. gallons per day, with an inter-quartile range from 33.5 to 43.8, a 6% reduction compared with 1991 and similar to the 1998/9 data for England and Wales, where the PCC varied from 33 to 42 U.S. gallons per day.

The survey also illustrates the provision of appliances within the dwelling. It confirms that socio-economic group and household characteristics are more important than geographic location. It also highlights our changing living practices. The traditional Saturday night bath and Monday clothes washday are shown to be well and truly things of the past. Showers have successfully penetrated the market; in 1982 only 32% of dwellings had a shower, increasing to 53% in 1991 and 66% in 1999, with 10% of dwellings having two. The majority was conventional or instantaneous, with 10% being power showers, i.e. showers where the flow rate is enhanced by pumping. The preponderance of the traditional in-house storage tank to supply water to non-drinking outlets limits shower flow rates. Direct mains feed to in-house plumbing is becoming more common; however, the survey was unable to identify these systems due to a lack of household awareness of their installed plumbing.

While effectively all dwellings have a bath, its use has declined from 0.71 uses/household/day in 1982 to 0.62 in 1999. Shower use has risen from 1.07 uses/household/day in 1982 to 1.55 in 1999, indicating a possible change in attitude toward personal hygiene.

Similar patterns can be seen in clothes and dishwashing. The washing machine is present in almost all dwellings, with 97% of these being automatic front-loading models. Their use has increased to almost one use/household/day, suggesting a more spread out washing activity than in previous decades. Dishwasher ownership escalated from 2% of households in 1982 to 26% in 1999, with daily usage decreasing from 0.78 uses/household/day in 1982 to 0.7 in 1999, possibly reflecting a more casual approach to the benefits of a "stack and forget approach."

Weekend water use was 10% higher than during the week, with the morning peak moving from 8-9 a.m. to 10-11 a.m. The evening peak is between 6 and 7 p.m. in both cases but is less marked at weekends. The afternoon low is recorded between 2-3 p.m. in both cases, again less well defined at weekends.

Within water usage by appliance, the w.c. dominated at 31% and 4.4 uses per day, with baths at 15%, showers at 10%, washing machines at 22% and dishwashers at 8%. The w.c. and bath consumption percentage has fallen, while the shower and washing machine percentages rose. The reduction in water use between baths and showers and improvements in washing machine design account for the fall in national domestic water consumption noted by the survey.

The survey concluded that reducing w.c. flush volume would have a central effect on overall water consumption. Currently in Scotland, the norm would be 2.4 U.S. gallons. There is the suggestion of a growing awareness of environmental issues and some evidence that the public notes the consumption ratings attached to washing and dishwashing machines.

While the popular opinion is that there is no shortage of Scottish water, water conservation is essential to a sustainable urban infrastructure. The economic benefits are clear. Surveys such as these allow us to assess and guide the required legislation.