Water affordability and human right to water implications in California

Abstract

Water affordability is central to water access but remains a challenge to measure. California enshrined the human right to safe and affordable water in 2012 but the question remains: how should water affordability be measured across the state? This paper contributes to this question in three steps. First, we identify key dimensions of water affordability measures (including scale, volume of water needed to meet 'basic' needs, and affordability criteria) and a cross-cutting theme (social equity). Second, using these dimensions, we develop three affordability ratios measured at the water system scale for households with median, poverty level, and deep poverty (i.e., half the poverty level) incomes and estimate the corresponding percentage of households at these income levels. Using multiple measures conveys a fuller picture of affordability given the known limitations of specific affordability measures. Third, we analyze our results disaggregated by a key characteristic of water system vulnerability-water system size. We find that water is relatively affordable for median income households. However, we identify high unaffordability for households in poverty in a large fraction of water systems. We identify several scenarios with different policy implications for the human right to water, such as very small systems with high water bills and low-income households within large water systems. We also characterize how data gaps complicate theoretical ideals and present barriers in human right to water monitoring efforts. This paper presents a systematic approach to measuring affordability and represents the first statewide assessment of water affordability within California's community water systems.

Fig 1. Box plots for crude (unadjusted) affordability ratios across income levels, by systems size.

Affordability ratios (AR) estimate monthly water bills for 6 HCF relative to three income levels: AR_MHI = median household income level; AR_CP = county poverty level; and AR_DP = deep poverty level. Highest value for AR_DP (45.85%) not shown for readability. Long dashed lines represent common thresholds for households earning median household incomes within a water system–1.5% [34] and 2.5% [54]. Dot-dashed lines represent the commonly referenced 3% threshold–which compares water bills (sometimes including sanitation) to income (often disposable income) [57, 59].

Fig 2. Percentage of households below county poverty threshold (HH_CP) vs. affordability ratio at county poverty threshold (AR_CP), by community water system size (n = 1,501).

Color fill shows the number of systems in each hexagon. Strip text above plots indicate community water system size by population served: very small = 25–500 people; small = 501–3,300 people; medium = 3,301–10,000 people; large = 10,000+ people.