Analyzing Trends in Residential Water Demand

The results of this work have already impacted water planning in Arizona. Municipal providers have updated their future water supply projections; ADWR has cited the work in its Tucson AMA management plan; the CAP is incorporating results into the municipal component of its water supply-and-demand model; and ADEQ is contemplating how to update its assumptions about wastewater flows generated by new development.


Long-term declines in household-level water demand in Arizona and across the Southwest have created uncertainty for municipal providers, wholesalers, wastewater facilities, and regulators. This trend poses numerous planning challenges because it impacts decisions about implementing capital improvements, acquiring new supplies, setting rates, designing conservation programs, and reusing reclaimed water.


M&A’s expertise in municipal water demand and dynamic simulation modeling was used to forecast changes in demand and to evaluate the principal causes and likely extent of the declines.

  • Investigated the factors that underlie the declining water demand
  • Compiled data on critical components of indoor and outdoor use on a single-family-residential basis
  • Researched penetration and water use rates for various household fixtures
  • Used Google Earth imagery to inventory turf and swimming pools and assess the frequency of pool removals
  • Evaluated the current and projected demographics and assessed the associated impacts on various components of per-household water demand
  • Developed dynamic simulation models to forecast the rates of change in per-household water demand and support provider-driven scenario testing
  • Provided guidance for developing and assessing the impact of conservation programs