공업용수에 관한 설문은 직접적으로 WTP를 묻는 방법을 취하여 지나치게 작거나 큰 값의 영향을 덜 받는 중앙값을 대표 WTP로 계산하였다.
For the industrial water questionnaire, the WTP was directly asked for, and the median value less affected by excessively small or large values was calculated as the representative WTP.