City seeks to dry up leaks from sewers

San Mateo is looking to engage more private property owners as it forges ahead with its Clean Water Program, a nearly $900 million effort to prevent raw sewage and untreated wastewater from seeping into the environment.

The hallmark of the 10-year capital improvement program is a major overhaul of its wastewater treatment plant, which will include increasing capacity and storage while possibly instating recycled water technology.

But officials are also aiming to zero in on ways property owners can help by encouraging them to repair private leaky lateral lines and reduce stormwater from infiltrating the system.

On Monday, the council met for an update on the Clean Water Program and to consider issues with privately-owned pipes by discussing a point-of-sale ordinance and cost-sharing incentives. No formal decisions were made and further outreach is needed before officials consider new rules.

San Mateo suffers from sanitary sewer overflows, particularly during wet weather when stormwater blends with wastewater and its facilities can’t process it fast enough. In 2009, the state issued a cease-and-desist order prompting the city to work diligently to prevent refuse from contaminating the environment.

“We’re already doing a lot of things under the Clean Water Program to address rehabilitating broken [public] sewer lines and there are multiple sources where water gets into the system,” said Cathi Zammit, a senior engineer and the program manager. “Private sewer laterals are part of the overall conveyance system, but being the privately-owned portion, it’s how can we as a city help to promote good stewardship and good participation of the public in helping to fix all these laterals?”

It’s difficult to determine the exact effect leaky laterals and illegal connections are having on the system, but the goal is to expand the city’s ability to locate potential sources, she explained.

Staff will consider different types of ordinances, but a preliminary framework might include making all property sales, including residential as well as commercial, conditioned upon inspections of the site’s sewer lateral. Inspection are often done with either a video camera or a pressure test, and any faulty pipes would have to be repaired as part of the property transaction, said Public Works Director Brad Underwood.

The city is committed to helping all property owners interested in reducing their impact on the environment and currently offers a popular cost-sharing program to help fund lateral repairs, Underwood said.

San Mateo has a $500,000 fund it replenishes annually to split the costs of the repairs, but the money frequently dries up quickly. Repairs vary greatly based on multiple factors, but they often average about $7,000. The city typically helps fix about 130 to 140 private laterals a year, but there’s a need for more as the fund is often depleted before the year’s end, said Underwood and Zammit. 

The issue of stormwater seeping into faulty private laterals has been an ongoing discussion in the city and the public recently piqued their interest during meetings about a less popular plan to install an 5 million gallon underground sewage storage tank, which the city is now looking to place at the San Mateo County Event Center parking lot. With residents’ increased interest in mind, staff is considering asking the council to possibly expand the city’s contribution to the cost sharing fund as well as discuss point-of-sale ordinance, Underwood said.

“As we hear more from the public and their interest to improve the system, we thought this would be another tool in the tool box,” Underwood said.

Overhauling the system

The city is progressing with the Clean Water Program, which aside from conveyance improvements includes overhauling the Detroit Drive wastewater treatment plant.

The goals of the project are threefold — replace aging infrastructure, increase capacity while reducing sewage overflows into the Bay, and meet sustainability goals by implementing new technologies.

Officials are moving into the 60 percent design phase and released preliminary renderings of the proposed plant that will go on a vacant portion of the existing site. The new facility will remain about the same size and footprint of the existing building, and certain parts of the current plant will remain in use to increase storage and capacity, said Zammit and Underwood. 

The city is also striving to incorporate sustainability at the site, having already installed a biogas digester that uses the treatment process to create fuel for city vehicles. It’s also looking to install a bioreactor membrane, which is a basic micro-filtration system that can be used to turn wastewater into non-potable recycled water for irrigation purposes, Zammit explained. The city doesn’t currently have a purple pipe system to convey the recycled water. However, it’s looking to collaborate with other agencies — including the San Francisco Public Utilities Commission, the California Water Service Company and the Bay Area Water Supply and Conservation Agency — to consider how to use this recycled water, Underwood said.

Aside from supporting San Mateo, the city’s plant services thousands in Foster City, Hillsborough and the Crystal Springs Sanitation District. Foster City, a 25 percent owner, as well as the other stakeholders will contribute to the $900 million price tag. Rate increases have hit double digits in many of the serviced communities, including San Mateo marking a nearly 36 percent hike to offset revenue reductions stemming from the drought. Officials are hopeful they’ll secure highly competitive state revolving loans for at least a portion of the cost, but could also rely on traditional higher-rate loans if needed.

The entire Clean Water Program is a 10-year capital improvement plan and Zammit said they anticipate beginning construction on the plant in late 2018, which could last about three or three-and-a-half years. It must first go through a design review process, which it recently began with the city’s Planning Commission last month.

Aside from increasing capacity and preparing for future regulatory requirements over how governments dispose of waste, a vital benefit will be to reduce sewer overflows into the Bay during extreme storms, Zammit and Underwood said.

Visit cleanwaterprogramsanmateo.org for more information.

samantha@smdailyjournal.com

(650) 344-5200 ext. 106

Twitter: @samantha_weigel