Domestic WC usage patterns

Despite contributing 30–40% of the total wastewater flow to building drainage systems, little is currently known concerning the detailed usage patterns of the domestic WC. A diary survey of WC usage was carried out on 135 households in southern England over seven consecutive days. Usage was categorised as urine only, faeces only, combined urine and faeces, and other. The urine mode of use followed the expected bimodal pattern of morning and evening peaks, whilst the the number of faecal related flushes peaked only in the morning with no corresponding evening rise. Weekend patterns were shown to differ from week-day usage, particularly in terms of the timing and magnitude of the morning peak. Females were found to use the WC 17% more often than males, whilst males use it 7% more in faecal related mode. Differences were also established between age groups with elderly people apparently having the highest WC usage. The application of cleaning agents was also shown to follow a distinctive diurnal pattern.