Sanitarian warns Sisters not to neglect drainfields

Don't neglect your drainfield now just because the City of Sisters plans to build a sewer.

That could be a very, very expensive mistake.

"We don't have a sewer yet. Until such time as we are actually hooked up to a sewer, we still have to use drainfield rules," said John Mason, County sanitarian for the Sisters area.

The one exception is the area set aside for a reserve drainfield.

"Once we know a sewer is going to be provided within five years, we can eliminate the requirement for a reserve area," said Mason.

But if a drainfield fails today, or next year, or the year before a sewer is actually built, Mason warns that the business or homeowner will still be stuck with putting in a full-size replacement.

"The law doesn't give us any leeway as far as downsizing the system, until a sewer comes," Mason said.

The reason a full-size system would be required, Mason said, is because septic system size requirements are based on estimated daily maximum flow and ability of soil to absorb and dissipate that flow, not the annual or lifetime capacity.

He said a maximum load of effluent, if it were delivered in the morning, could saturate the soil. It would take a while for the soil to recover. Downsizing a system significantly would simply guarantee what Mason called a septic system "blow out."

"My concern is that I don't want the citizens of Sisters to think they don't have to keep maintaining their drainfields or septic tanks. If your system goes bad today, you will have to put in a full-size system. For lots less than a half acre, that means a sand filter replacement, to the tune to $7,000," Mason warned.

Mason said that pumping out a septic tank for $200 is much cheaper than a $3,000, or $4,000 or a $7,000 replacement system.

The county has a hand-out on care and maintenance of a drainfield, said Mason.

"The real killer is a lot of water use. A leaking, running toilet will kill a system faster than anything. Over-watering a lawn over the drain field, or pouring fats and oils down the sink that are not digested," will all lead to premature failure, warned Mason.

"Think of a drainfield as a liquid compost pile. If it is not going to rot, don't put it down there," he said.