On-Site Water Systems – Its Impact on Water and Infrastructure Asset Management

Many cities are searching for ways to develop and manage local resources.

The Water Environment Research Foundation (WERF), through its sustainable integrated water challenge, is seeking to help cities and towns change the way that they manage their water by gearing them towards the integration of infrastructure.

In San Francisco, an exciting new project called “Blueprint for On-Site Water Systems” is well underway.

It is primarily designed to help communities with developing a local program to manage and oversee on-site water systems that protect public health.

On-site water systems promote water resiliency through many channels.

In 2012, the San Francisco Public Utilities Commission encouraged an effort to create a local program for regulating on-site water use called the “Nonpotable Water Program.”

Water Online reports:

“The Nonpotable Water Program creates a streamlined process for commercial, multi-family, and mixed-use developments in San Francisco to collect, treat, and reuse water for toilet flushing, irrigation, and other nonpotable uses.

The program allows the collection and treatment of alternate water sources to occur within one building or for multiple buildings to share treated alternate water sources for nonpotable uses.

Established through an ordinance adopted by the San Francisco Board of Supervisors, this voluntary program encourages the use of water generated on site to expand water savings and further diversify SFPUC’s water supply portfolio:

• Rainwater — precipitation collected from roofs or other man made above-grade surfaces
• Stormwater — precipitation collected from at- or below-grade surfaces
• Gray Water — wastewater from bathroom sinks, showers, and washing machines
• Blackwater — graywater and wastewater from kitchen sinks and toilets
• Foundation drainage — nuisance groundwater that floods basements

Developers and designers are responding to San Francisco’s program by incorporating innovative on-site nonpotable water use systems into their projects — such as treating gray water for toilet flushing or using rainwater for spray irrigation.

More than 20 new developments in San Francisco are proposing to collect, treat, and use a variety of alternate water sources for nonpotable applications.”

These projects could well be the future of water management for many cities around the U.S.

What are the implications of on-site water systems on the overall infrastructure asset management plan?

For municipal infrastructure asset management – when alternative, privately owned and managed, nonpotable water use systems are incorporated into overall rainwater or stormwater catchment management planning – then the information on these systems needs to be monitored and noted in your infrastructure asset management plans.

The reason for this is monitoring and infrastructure asset management is – as these systems become more common, the impact on rainwater run-off dynamics will become greater.

Success or failure of private systems then has more potential to impact on the effective performance of municipal systems.

This monitoring and information collection can sometimes be difficult – particularly if the permits for such systems are issued by other organizations or other parts of your organization.

This is just something to think about and watch out for in your infrastructure asset management practice – are there private systems that impact your infrastructure, or infrastructure performance.

If yes, what do you need to know about these private systems, and what monitoring (if any) is required.