Updated: Saturday, September 11, 2010 9:29 AM
By STEVE BROWN
Capital Press
YACOLT, Wash. -- Though "common wisdom" often advises rural residents to have their septic tanks pumped every one or two years, Tom Gonzales says that can often be extended with proper maintenance.
Gonzales is program manager for Clark County, Wash., Public Health.
"Inspect your system, keep the bacteria healthy and happy, and pump when needed," he told the dozen or so residents at a session, which was co-sponsored by the Washington State University Clark County Extension.
Keeping a system maintained is good for the pocketbook, he said. It can cost between $5,000 and $25,000 to construct a new onsite sewage system.
Gonzales said a properly functioning septic system is critical for protecting drinking water. Bacteria in the tank break down organic solids into gas and liquid. The system separates solids (sand, gravel, dirt, bits of plastic) and scum (grease and oils) from the effluent, which is directed into a drainfield where it passes into the soil, which completes the treatment of the household's wastewater.
"Dirt is a great gift from Mother Nature to capture bacteria and viruses before they reach the groundwater," he said.
He listed several essentials to keep the system operating efficiently:
* Conserve water. Water-saving devices, reduced toilet reservoir volume, shorter showers and washing only full loads of dishes and laundry -- all these extend the life of the drainfield and decrease the possibility of system failure. Having several people in one household will necessitate pumping the tank more often.
* Keep records. Documents specifying the tank's size and location are usually available at the county health agency, Gonzales said. It's also wise to record inspections and maintenance.
* Inspect the system regularly. Checking levels of scum and sludge, inspecting baffles and checking the drainfield can detect problems before they become expensive. "Homeowners can take a course and inspect their own gravity systems every other three-year cycle," he said.
Other systems -- pressure, aerobic and Glendon systems -- require trained inspectors. The soil type and conditions determine which system is required.
* Pump when needed. Routine pumping can prevent clogging of the drainfield or sewage backing up into the home.
* Service filters. If the tank has an outlet filter, it should be cleaned or replaced at least once a year.
* Never flush harmful materials into the tank. Grease, cooking oil, newspaper, paper towels, rags, coffee grounds, sanitary napkins and cigarettes cannot easily decompose in the tank. Solvents, paints and pesticides can pollute the groundwater. The use of bleach and antibacterial soap should be minimized. Gonzales recommended using vinegar for its antiseptic properties.
He stressed that septic tank additives are not necessary, and they can destroy the biological function of the tank, allowing raw sewage to flow directly into the drainfield. Organic solvent additives can also kill the healthful bacteria and may contaminate groundwater.
A critical safety issue: Never enter any septic tank. The gases or lack of air can be fatal. Any work to the tank, he said, should be done from the outside.
With proper care, he said, the septic system should have a life span of 25 to 30 years.
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