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Purifying used water is a critical component to saving money

A new water-reuse system is gaining popularity amongst companies who are looking to get the most value out of their water usage. This technology may help your company save money on all water uses by reusing waste water.

We spoke with Paula Kehoe, the Director of Water Resources with the San Francisco Public Utilities Commission (SFPUC). She is responsible for diversifying San Francisco’s local water supply portfolio through the development and implementation of conservation, groundwater, and recycled water programs.  Paula spearheaded the landmark legislation allowing for the collection, treatment, and use of alternate water sources for non-potable end uses in buildings and districts within San Francisco.  


Christopher P. Skroupa: Your report says, “Onsite non-potable water systems are changing the way we think about matching water supplies with the right use.” How has this technology affected water strategies, and how has the long-term value of water been influenced by this technology?

Paula Kehoe: The increased focus on water reuse around the country is exciting. More projects being implemented means the acceptance of water recycling is increasing, and the technology continues to advance as well. The next big challenge is looking beyond the more traditional recycled water projects that focus on irrigation, and moving to technological innovations for cost effective and energy efficient onsite reuse of purified water. San Francisco is breaking ground in both of these areas. Our Non-Potable Program provides a framework for the collection, treatment and use of alternative water sources for non-potable applications such as toilet flushing and irrigation.

We use a treated wetland system in our own headquarters building, and are paving the way for other large commercial buildings in San Francisco to do the same. In a dense urban setting, like San Francisco, our goal is always to foster the right water for the right use. Developing a pathway to use alternative water for toilet flushing, and save our potable supplies for their highest use, just makes sense.

Purified water is an emerging area that will see a lot of progress over the next decade both in technology development, and on the regulatory front. To support this, the SFPUC is participating with other utilities on research efforts. We are also conducting a research project to examine the feasibility of developing purified water at the building scale.

Skroupa: Can you touch upon some of the challenges that companies will encounter when trying to use this technology, and how they might overcome those challenges? Challenges within policy, strategy use and physical use?

Kehoe: Despite the broad range of benefits, the adoption of onsite water systems has been constrained by policy and regulatory barriers. The National Blue Ribbon Commission for Onsite Non-Potable Water Systems advances best management practices to support the use of onsite non-potable water systems for individual buildings, or at another appropriate local scale. The goals of the Blue Ribbon Commission are to:

  • Identify the opportunities onsite non-potable water systems can play in communities and benefits to utilities;
  • Craft model state guidance and policy framework for the management and oversight of distributed non-potable water systems – i.e. water quality criteria, monitoring and reporting requirements, and operational and permitting strategies – and;
  • Identify additional research needs in the field.

Skroupa: The data is clear that this technology is successful, and you’ve asked the perfect question [in the report]: “If proven technology is available and the benefits are evident, why then haven’t we seen more widespread implementation of these systems?” why haven’t more companies implemented these systems?

Kehoe: Currently, there are no overarching national standards for water quality, or required treatment for alternate water sources. Existing plumbing codes often include requirements for water quality and construction, and allow end uses for alternate water sources. Typically, onsite water systems may be incorporated into plumbing permits and often require a special permit to operate from a state or local public health agency – a jurisdiction which has authority.

The additional public health permit is often required, as plumbing codes do not cover ongoing operation and maintenance of alternate water source systems to ensure the protection of public health, and the public water system post-construction. Building codes, including plumbing codes, are generally enforced at the time of construction, and are not intended to mandate on-going operation and maintenance.

Through our national work we collaborated with the National Water Research Institute (NWRI), who led an independent expert panel to conduct research and develop recommendations for appropriate water quality standards. This research resulted in the publication entitled Risk Based Framework for the Development of Public Health Guidance for Decentralized Non-potable Water Systems funded by the WRF and Water Environment and Reuse Foundation – the WE&RF.

The report provides information and guidance through a risk-based framework to help state and local health departments develop onsite non-potable water systems that are adequately protective of public health. The framework includes risk-based performance criteria that are consistent with the most advanced and protective public health standards to ensure safe water is delivered at all times.

The framework also fits the Water Safety Plan approach promoted by the World Health Organization. Unlike current limited standards for onsite non-potable water systems, which often rely on end-point assessment of water quality, the risk-based framework focuses on a systems-based approach to setting water quality targets that will help reduce the public’s exposure to pathogens. While this framework is new for onsite non-potable water systems, the approach is based on widely accepted practices for both drinking water and potable reuse.

The National Blue Ribbon Commission is currently crafting model state guidance and policies on mandatory water quality criteria for non-potable water systems that can be transferable from state to state. The model state guidance will focus on creating consistency in the elements of an oversight and management program including water quality performance, monitoring and reporting requirements, as well as present various implementation pathways to establishing a successful local program. Additional items that will be included in the model state guidance are templates for an engineering report and operations and maintenance manual, and other requirements for design, construction and operation.


Kehoe’s colleague, John Scarpulla, Government and Public Affairs Manager, San Francisco Public Utilities Commission, will be a panelist for the discussion The Integration of Centralized and Decentralized Water System Approaches at the Water & Long-Term Value conference in San Francisco, CA on October 24-25.

Originally published on Forbes.com. More articles by Christopher Skroupa on his Forbes column.