A bill before the Senate Local Government Committee would force home sellers and their real estate agents to disclose available basic data about septic systems, while protecting them against liability if they do so.

“People need to know something about their septic systems,” said Sen. Ron Erickson, D-Missoula, the sponsor of Senate Bill 191.

He told the panel some 80,000 lots developed since 1990 have septic systems.

A survey about a decade ago in Lewis and Clark County showed that one-third of people with septic systems did not know the location of the systems, said Steve Kilbreath, program manager for the Department of Environmental Quality subdivision and public water supply engineering program, speaking in favor of the bill.

Properly installed and maintained septic systems contribute to public health, he said.

Glenn Oppel, government affairs director for the Montana Association of Realtors, said buy/sell agreements already disclose such information in the overwhelming majority of transactions. He called the bill unnecessary and said it would expose the real estate agents to liability if they provided erroneous information.