The O'Malley administration is proposing a regulation that in most of the state would require builders of new homes using septic systems to install more costly models that reduce water pollution.
The Maryland Department of the Environment acknowledges that the requirement could add thousands of dollars to the cost of a new home. Maryland builders contend that the added cost is not justified by scientific findings.
The proposal would accomplish by regulation a goal that environmental advocates tried to achieve in 2009 through legislation: to require use of the new technology virtually statewide.
The rule, proposed Friday, is another step in the administration's effort to curb nitrogen pollution from septic systems in the watersheds of the Chesapeake and Atlantic coastal bays. It follows the General Assembly's passage this month of the governor's bill setting limits on where large developments using septic systems are permitted.
That measure, scaled back by the legislature to reduce the state's direct role in determining the placement of septic systems, did not address the issue of differing septic system technologies. The legislation was nevertheless hailed by environmentalists as a significant victory.
Jay Sakai, director of the Water Management Administration at the Maryland Department of the Environment, said the proposed regulation expands on a 2009 law requiring the use of "best available technology" septic systems. That law requires such technology to be used in all new and replacement systems installed in critical areas — locations close to the bays or the streams that run into them.
Sakai said the proposed regulation would apply to septic systems in new homes outside the critical areas. Owners of existing homes with failing septic systems would still be allowed to replace them with the cheaper conventional technology. A few places in Maryland that are not in the Chesapeake or coastal bay watersheds would be exempt.
The proposal has been submitted to the joint General Assembly committee that reviews and approves such regulations.
Conventional septic systems are effective at breaking down solid wastes and filtering out bacteria and other pathogens before they can enter ground water, Sakai said. However, they do not remove nitrogen, one of the primary pollutants in the bay.
Sakai said best available technology systems — a term of art for a variety of technologies — remove at least 50 percent of the nitrogen from wastewater before it can reach the bay.
By extending the requirement of best technologies statewide, the administration is going beyond what the legislature decided to do in 2009. That year, lawmakers took a bill — not proposed by O'Malley — that originally would have applied virtually statewide and limited it to the critical areas.
Sakai said the Maryland Department of the Environment has the authority to impose the change through regulation.
Katie Maloney, a lobbyist for the Maryland State Builders Association, said it makes little sense to require the use of the advanced technology for new homes in places such as Frederick County.
"We would have preferred that the use of these septics be science-based," she said. "Requiring them in a blanket way, we think, is not cost-effective."
She said the cost of installing a new system using the advanced technology is roughly double the cost of using the conventional method. The Department of the Environment estimates the cost of a system using the more modern technology at about $13,500.
Jenn Aiosa, chief scientist for the Chesapeake Bay Foundation, welcomed the proposal.
"At the end of the day, we don't believe it is asking too much for new construction to pay for their actual pollution load," she said.