By Lauren McSherry

Most people have heard about how sewers clogged by roots can cause a big stink. How about grease?

Dave Ross, city engineer for Los Altos Hills, suspects that some companies hired by local restaurants to haul away used cooking grease may not be disposing of the waste properly and could be dumping it illegally into residential sewer systems in remote, rural areas, such as the Hills.

Independent contractors hired by the grease-hauling companies are required to drain the waste from underground tanks and cart it to Palo Alto’s Regional Water Quality Control Plant or other local treatment plants.

Instead, some contractors pocket the money it would cost to transfer the waste and illegally dispose of it in residential neighborhoods.

A single restaurant tank holds between 1,500 and 3,000 gallons of grease, Ross said.

In March, an independent contractor for Hayward-based A-1 Septic Tank Service was convicted of illegally dumping 3,000 gallons of grease from Palo Alto Hills Golf & Country Club.

The grease blocked the sewer line, and several thousand gallons of raw sewage and grease overflowed onto Page Mill Road, contaminating Matadero Creek.

The perpetrator was caught, prosecuted and faces a fine and jail time, but such outcomes are rare, Ross said.

“There are about eight companies hauling, and it is very difficult to know which are bringing their grease to the treatment plant or taking it to our sewers,” he said. “Unless you have somebody following every truck around, it’s very difficult to catch these guys.”

Unlike Los Altos streets, Hills streets are not regularly traveled and dumpers are not likely to be seen.

“It just so happens that Los Altos Hills is an easier place to dump than anywhere else,” said Jim Porter, Los Altos city engineer.

Meanwhile, Los Altos Hills residents John Harpootlian and Duffy Price said they have a mini-Chernobyl in their back yards, and Ross suspects that an illegal grease dumper may be the culprit.

As of the Town Crier’s press deadline, city staff were investigating a possible April 18 grease-dumping incident near the Harpootlian and Price homes.

Ross, a member of California’s Fats, Oils and Grease Committee, said grease dumping is not only a statewide problem, it’s worldwide a problem.

Locally, treatment facilities in San Jose, Sunnyvale and Palo Alto are examining a voucher system to discourage dumping, he said.