Collecting household water usage data: telephone questionnaire or diary?

Area of Science:

• Environmental Health
• Risk Assessment
• Water Resource Management

Background:

• Quantitative Microbial Risk Assessment (QMRA) models health risks using exposure data.
• Urban non-potable water use duration and frequency are key data gaps in QMRA.
• Accurate exposure estimates are crucial for effective QMRA.

Purpose of the Study:

• To compare household water usage data from computer-assisted telephone interviews (CATI) and 7-day water activity diaries.
• To evaluate the impact of different survey methods on exposure estimates.
• To assess the cost and logistical feasibility of each data collection tool.

Main Methods:

• Surveyed 232 households in an Australian dual reticulation system using both CATI and a 7-day diary.
• Collected data on household use of recycled water for toilet flushing, garden watering, outdoor activities, and laundry.
• Assessed agreement between CATI and diary responses for water usage.

Main Results:

• Agreement between CATI and diary responses was higher for frequent water activities and those with standard durations.
• Toilet flushing showed lower agreement between the two methods.
• Diary administration had a higher unit cost than CATI, excluding initial recruitment.

Conclusions:

• Remote diary completion is feasible with clear instructions and well-designed forms.
• Monetary incentives can achieve good diary return rates, facilitating collective household water usage recording.
• Water activity diaries are a valuable tool for collecting water usage data, potentially combined with mail or online recruitment.