Waste less, pollute less: A guide to reduce urban water use

Oct. 9, 2014

Water conservation can advance Clean Water Act compliance.

It’s no secret that there’s a crisis concerning the U.S.’s municipal water, wastewater and stormwater infrastructure. Nearfailing grades were present on the American Society of Professional Engineers’ annual infrastructure report card. Almost $700 billion in investments are in need over a 20year period estimated by the Environmental Protection Agency (EPA).

Water supplies in some regions are faced with crippling drought. Others are confronted with more rain than they can handle, triggering sewage overflows and flushing polluted urban runoff into waters used for drinking, recreation and fishing. Population growth and land use patterns are increasing the pressure. Climate change is already intensifying extreme weather patterns that affect water availability, water demand and water quality — not to mention the threat of direct flood damage to water and wastewater treatment plants posed by extreme storms.

To solve these challenges we need to think about water management much more holistically than we have in the past. In the urban context we often think of water supply and water quality as separate issues, each with its own challenges and distinct infrastructure assets. However, the reality is that quantity and quality — having enough water and having clean water — are closely linked.

Urban water conservation strategies and benefits

Cities and utilities are realizing more and more the value that many costeffective urban water conservation strategies bring to 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 water conservation benefits is attractive both in the arid western states and in the more waterrich east.

My organization, Natural Resources Defense Council, recently released a publication aimed at raising awareness of these opportunities. Aptly titled, “Waste Less, Pollute Less,” the report puts urban water conservation strategies in the context of urban water pollution control. It shows how cities and utilities can use urban water conservation to help meet Clean Water Act standards that protect public health and the environment. The report also demonstrates how state and federal policymakers can leverage water pollution control programs and funding to achieve water use reductions.

By improving drinking water distribution systems and reducing, or limiting the growth of, indoor water use, cities can reduce strain on sewage collection systems and sewage treatment plants. This not only helps the drinking water utility, but also improves pollution control performance and reduces compliance costs for the wastewater utility.

For example, more efficient fixtures and appliances, reuse graywater for outdoor applications, onsite wastewater treatment and reuse for indoor applications, all result in a lower volume of municipal wastewater flows. Meanwhile, repairing leaks from drinking water distribution systems can reduce infiltration into underlying sewer pipes.

The resulting lower flows in sanitary sewers can have many likely benefits for wastewater utilities’ Clean Water Act compliance, including: Reduced volume of wet weather overflows due to lower dry weather base flows; reduced, deferred or avoided capital costs for new or expanded collection and treatment capacity that would otherwise be necessary to achieve or maintain Clean Water Act compliance and/or accommodate population growth; reduced energy demand (and associated operating costs) for pumping and treatment.

Lower volume, more highly concentrated wastewater flows — associated with improved indoor water use efficiency — also have the potential to improve efficiency of certain wastewater treatment processes at existing facilities, which would yield in lower operating costs and extended equipment replacement periods.

A good fit

In addition, “rightsizing” new wastewater infrastructure to account for trends in decreasing indoor water use — instead of relying on outdated rules of thumb that overestimate perhousehold demand — can stretch limited local, state and federal dollars to help more communities solve more water quality problems.

Turning to stormwater management, “green infrastructure” techniques that enhance local water supply by capturing rainwater for reuse or groundwater recharge or features that use native landscaping to reduce outdoor water demand, can simultaneously — and costeffectively — reduce stormwater pollution and sewer overflows. These approaches keep rainwater from overwhelming sewers and carrying pollution to local waterways, and instead use the rainwater as a productive resource.

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 percent 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 waterefficient toilets, both to reduce potable water demand and to avoid costly sewage treatment plant expansions. The state was able to defer billiondollar expansions of four sewage treatment plants by reducing dryweather sewage flows by 17 percent over five years. New York also anticipates further water conservation gains will reduce annual sewage overflows by 1.7 billion gallons, or eight percent, 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 “ultralow flush” toilets in all new buildings, to keep its water use level even as population surged by one million people. Additionally, the city’s strategy to reduce polluted runoff includes largescale 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, the synergies between water quantity and water quality have mostly been underappreciated.

Applying conservation solutions

Municipalities and utilities should incorporate water conservation strategies into compliance plans for reducing sewer overflows, rehabilitating or expanding wastewater treatment, collection infrastructure and controlling stormwater pollution. Likewise, the state and federal agencies that regulate local wastewater utilities and municipal storm sewer systems should seek every opportunity to incorporate water conservation tools into compliance and enforcement efforts.

An exciting new opportunity to accelerate these solutions arises from new federal legislation passed this summer. Congress added new water conservation provisions to the Clean Water State Revolving Fund (CWSRF), the chief federal program for clean water infrastructure funding. Under the new law, municipalities and utilities seeking CWSRF funding will be required to maximize water efficiency and reuse as part of all wastewater and stormwater infrastructure projects. Additionally, water efficiency and stormwater management projects are now eligible for loan forgiveness and negative interest loans (essentially, grants) under the CWSRF, not just low interest loans. EPA is likely to issue guidance in the coming months for implementing these provisions.

Finally, the private sector has an essential role to play. Utilities rely on engineering and consulting firms to develop compliance plans as well as design and implement new infrastructure investments. Firms — both small and large — that propose water conservation projects to improve municipal Clean Water Act compliance, or that otherwise help utilities “rightsize” their capital projects to account for water use efficiency gains, can build their business with utilities that are constantly searching for more costeffective solutions. Firms that cater to commercial, industrial or residential clients can integrate water efficiency into their engineering and operational designs or into choices of fixtures and appliances. This saves money for private clients by reducing their water bills and operational costs — and it contributes to lower water bills for everyone in the community by helping public utilities reduce their own costs. 

Ultimately, these privatesector and publicsector efforts can catalyze a broader market transformation in how we manage our urban water resources in this country. Waste less, pollute less.

Larry Levine is a senior attorney in NRDC's Water Program, working on urban water quality and water efficiency. His work focuses particularly on promoting the use of "green infrastructure" as a sustainable solution to polluted urban runoff and raw sewage overflows, implementation of states’ water conservation commitments under the Great Lakes Compact and policies to reduce water loss from municipal drinking water systems. He is a graduate of Yale Law School and Tulane University. Larry blogs on green infrastructure and water efficiency at http://switchboard.nrdc.org/blogs/llevine/.

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