With many of the sewage pipes under our roads and houses close to 100 years old, replacing them has become a top priority for residents and for the sanitary district. But, tearing up roads to replace pipes can be disruptive, loud, and a little bit smelly for residents – not to mention expensive.
That’s why the Ross Valley Sanitary District has been running a pilot trial with pipe-bursting, a system that pulls a new pipe through old pipe, bursting the old pipe in the process. The process is faster, requires less excavation, and allows a larger pipe diameter to replace a smaller one. The sanitary district board approved a trial of the process over a year ago, which would use rented pipe bursting equipment and an in-house repair crew who would learn the new equipment, to “see if we could really save those dollars,” said General Manager Brett Richards.
Since 2006, the district has replaced about 15.5 miles of sewage pipe. In addition, the district has replaced another two miles worth of “in-lieu” pipe – meaning that by a consent decree the district is allowed to count the money spent on replacing pump stations and other facilities as pipe replacement. In the last five years, $27.8 million has been spent on replacing pipes and facilities.
With over 200 miles of pipe, 139 miles of which is less than 10 inches in diameter, it will take 70 years to upgrade the entire system.
Richards emphasized that two miles of pipe replacement per year is “an aggressive average” and the district is well ahead of other similar district.
“Sewer districts nationwide need to think creatively to get more pipe in the ground faster and at a lower cost to the ratepayer,” said Richards.
This is where pipe-bursting comes in. The district determined that it would be most beneficial to use the technology on pipes smaller than ten-inches in diameter. The district will continue to contract for specialty and large-scale pipe replacement projects, such at the Kentfield Force Main and the Woodland-College-Goodhill projects, which were both recently completed.
After an 18-month trial of pipe-bursting, using the in-house crew – much of which was done on Bothin Road in Fairfax – the cost of replacing a mile of pipe with the technology dropped from $1.4 million to $847,000.
Richards also said that it took the in-house crew some time to learn the equipment, so “with experience and practice, natural efficiency will lower that cost.”
The board voted to approve a plan that, in addition to continuing to replace two miles like usual, would hire five additional employees to run a full-time pipe-bursting program, replacing an additional mile of pipe every year. This would bring the district up to 40 full-time employees.
Municipal Sewer and Water recently recognized the Ross Valley Sanitary District for their pilot pipe-bursting program, calling it a cost-effective solution. Although the technology has been around for years, it is uncommon for a district to use it’s own crew to take advantage of pipe-bursting, instead of contracting the work out.
“So, we’d be leaders,” said Board Member Pam Meigs of the program.
In an effort to speed along the replacement of all the old pipes in the system, the district also has a lateral grant replacement program. The program offers up to $4,000 or 50 percent of the cost of the pipe replacement for private homeowners to replace their personal, lateral lines that connect to the main sewage lines. Get more information about the program here.
