Socio-hydrological drought impacts on urban water affordability

Abstract

In water-stressed regions, droughts pose a critical challenge to urban water security for low-income households. Droughts reduce water availability, forcing water providers to invest in additional supplies or enact expensive, short-term emergency measures. These costs are frequently passed on to households through increased rates and surcharges, driving up water bills for low-income households and altering patterns of water consumption. Here we have developed a socio-hydrological modelling approach that integrates hydrology, water infrastructure, utility decision-making and household behaviour to understand the impacts of droughts on household water affordability. We present here an application based on Santa Cruz, California and show that many drought resilience strategies raise water bills for low-income households and lower them for high-income households. We also found that low-income households are most vulnerable to both changing drought characteristics and infrastructure lock-in.Unaffordable water prices threaten human health and well-being in the United States and beyond 1-5 . In California alone, one million people lack access to affordable clean drinking water 6 . Low-income households are disproportionately impacted by unaffordable water bills 4 , with one-third of water systems in low-income areas of the United States charging unaffordable rates 7 . Unaffordable water threatens health by limiting both domestic water use 8 and other essential household expenditures. Indeed, 14% of the US population reports that a US$12 monthly increase in water bills would reduce access to groceries and basic medical care 9 . Water bills are currently increasing faster than inflation 3 and the strain of climate change on water supplies threatens to accelerate cost increases.Droughts exacerbate affordable water access in many waterstressed regions by reducing water availability and increasing the cost of supplying water. Water providers must use expensive short-term mitigation measures such as curtailment or invest in additional water supplies 10,11 to provide reliability, but these measures may increase water rates 12 . Counterintuitively, these measures can reduce household water security by making water unaffordable for more people 13,14 . This impact is supported by empirical evidence from recent droughts that showed that households in urban areas of California paid higher water bills during drought periods 15 .Household water-use behaviour compounds the affordability challenges created by droughts and disconnects household and utility water security. During droughts, households change their water use as a result of drought-related water restrictions 13,16 , responses to price increases 17,18 , and changing water use based on socio-economic and demographic factors [19][20][21] . Household changes in water use in response to exogenous factors alter utility revenue and potentially necessitate additional rate increases. Accordingly, quantifying water affordability requires explicitly incorporating household-level water...

Resilient water infrastructure partnerships in institutionally complex systems face challenging supply and financial risk tradeoffs

“…However, even under such optimistic conditions, the extreme levels of interannual hydroclimatic variability experienced in California 51,52 lead to signi cant decision-relevant uncertainty in cooperative infrastructure investment outcomes over the next several decades. Water providers therefore must nd a way to improve surface water reliability and reduce groundwater overdraft without exacerbating the growing water affordability concerns for agricultural and urban water users [12][13][14] . We caution that decisionmakers should carefully consider the impacts of uncertainty and nancial risk before committing to signi cant debt associated with new infrastructure partnerships.…”

“…When investing in new infrastructure, water providers must be careful to balance the bene ts of supply investments with their associated long-term debt obligations that must be repaid using water sales revenue 8,9 . This nancial risk is especially important in light of concerns over the creditworthiness of drought-exposed water providers, concerns that can lead to higher borrowing rates and contribute to growing water affordability challenges in many regions [10][11][12][13][14] .…”

Fast in the pandemic, durable after droughts, inequal during economic downturn. A 20 year multi-dimensional retrospective analysis of water demand change in Southern California

“…Detailed information about individual households' water demand and its determinants cannot be captured at such scale of aggregation. Yet, determining changes in water consumption behavior for different types of water users can be a valuable input for future infrastructure planning and management of water demand under changing climate and socio-technical conditions, as well as for understanding inequalities in household water access and affordability (Rachunok andFletcher 2023, Zaniolo et al 2023).…”

Perubahan Morfologi Koridor Jalan dan Pengaruhnya Terhadap Aktivitas Komersial di Jalan Lawu Karanganyar

“…Water scarcity has become a threat to the whole world since global warming and climate change have hit the world recently [1]. Water scarcity also make water unaffordable for low-income household and people in developing countries due to the cost of supplying water or the lack of quantity and quality of groundwater [2] [3]. Indonesia is not free from this risk, even though this region is generally rich in water sources [4].…”