Urban Water Conservation Strategies Can Help Address Both Water Quality and Quantity Needs

In many parts of the United States, cities and suburbs -- and the wastewater and stormwater utilities that serve them -- are among the largest sources of water pollution. They need hundreds of billions of dollars to repair, maintain, and improve their infrastructure to comply with Clean Water Act standards that protect public health and the environment. In many cases, they must maintain that compliance while accommodating population growth.

At the same time, many metropolitan areas are facing serious water supply challenges, in an era of chronic water scarcity, increased uncertainty in future water availability, and growing competition for water resources. As global temperatures continue to rise, precipitation patterns change, and water demands increase, more communities will be challenged to maintain adequate water supplies.  California’s current extreme drought is only the most dramatic example.

Fortunately, there are many cost-effective urban water conservation strategies that can help address both water quality and quantity needs. These strategies can simultaneously relieve stress on urban water supply systems, reduce costs to water and sewer customers, and keep pollution out of our rivers, lakes, and beaches.  That trifecta of benefits makes them attractive both in the arid western states, and in the more water-rich east.   

A new NRDC issue brief, “Waste Less, Pollute Less,” aims to raise awareness of these opportunities, by putting urban water conservation strategies in the context of the Clean Water Act.  It shows how cities can use urban water conservation to help meet Clean Water Act goals.  And it demonstrates how state and federal policymakers can leverage water pollution control programs to achieve water use reductions

Importantly, both indoor and outdoor water use are at play. 

Measures that curtail indoor water use -- such as water-efficient fixtures and appliances -- also reduce strain on sewage collection systems and sewage treatment plants, improving pollution control performance and reducing compliance costs.  And “right-sizing” new wastewater infrastructure to account for trends in decreasing indoor water use – instead of relying on outdated rules-of-thumb that overestimate per-household demand – can stretch limited local, state, and federal dollars to help more communities solve more water quality problems.

Outdoors, measures that enhance local water supply by capturing rainwater for reuse or groundwater recharge, or that use native landscaping to reduce outdoor water demand, can simultaneously -- and cost-effectively -- reduce stormwater pollution and sewer overflows.

Many communities have already taken advantage of these links between reduced urban water use and reduced urban water pollution.  Examples highlighted in “Waste Less, Pollute Less,” include:

  • The San Antonio Water System has kept water demand steady for 25 years, despite a 67% increase in the number or water customers, through an aggressive conservation program.  This has allowed the city to avoid up to $2.7 billion in additional water supply costs and over $1 billion in expanded wastewater treatment capacity costs.
  • New York has used rebates and regulations to promote water-efficient toilets, both to reduce potable water demand and avoid costly sewage treatment plant expansions.  It was able to defer billion-dollar expansions of four sewage treatment plants by reducing dry-weather sewage flows by 17% over five years.  New York also anticipates further water conservation gains will reduce annual sewage overflows by 1.7 billion gallons, or 8%, while saving millions of dollars in annual operational costs and far more in avoided capital costs.
  • Los Angeles, motivated both by pressure on its wastewater treatment plants and by water shortages, relied on tools such as mandatory fixture retrofits in existing buildings and use of “ultra-low flush” toilets in all new buildings to keep its water use level even as population surged by 1 million people.  Additionally, the city’s strategy to reduce polluted runoff includes large-scale stormwater capture and infiltration projects, which also serve the purposes of landscape irrigation (substituting for potable water) and groundwater recharge (enhancing local supplies).

While these cities provide inspiration, more commonly the synergies between water quantity and water quality have been under-appreciated.  With the release of “Waste Less, Pollute Less,” we aim to provide a corrective to this inattention – and a call to action. 

For example, as they have done increasingly with green infrastructure – another sustainable sustainable urban water management strategy – communities and regulatory agencies should incorporate water conservation strategies into permits, consent orders and decrees, combined sewer overflow (CSO) plans, and infrastructure financing programs under Clean Water Act.  (We recently suggested that the CSO permits for New York City, several New Jersey cities, and Sacramento should take this approach.  We’re awaiting a response from those states’ environmental agencies.)

Another opportunity arises from new federal legislation passed this summer.  Congress added new water conservation provisions to the Clean Water State Revolving Fund, the chief federal program for clean water infrastructure funding.  Implementing regulations from EPA are likely to follow, and we will be tracking these developments closely.  As my colleague Ben Chou explains here, the State Revolving Funds, if deployed wisely, can be a powerful tool to promote climate resiliency, including water conservation measures.

We look forward to working with water and sewer utilities around the country, as well as state and federal regulatory agencies, to raise awareness of untapped opportunities and implement innovative solutions.  And we look forward to partnering with academics and engineering professionals to deepen the technical understanding of these issues in the years to come.


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