Senate President Thomas V. Mike Miller said this afternoon that the governor's bill to limit septic systems will face strong opposition from other Democrats when it is debated later this week.

"It is going to be dicey, very dicey," Miller told reporters.

The legislation (SB 236) would create four development tiers in Maryland, allowing new septics in some parts of the state but not in others. It is a complex bill -- floor leader Sen. Paul Pinsky spent 15 minutes just describing what would be allowed in each tier.

Pinsky said the bill would halt rural sprawl, which he compared to measles -- with little dots of development scattered through farmlands and wooded areas.

Last year Gov. Martin O'Malley tried an outright ban on septic systems, but the legislature shelved it. Over the summer a task force re-wrote the bill and offered this year's more nuanced -- and more confusing -- approach.

Debate on the measure could start as soon as Wednesday, and could pit two Democratic committee chairs against one another. Sen. Thomas "Mac" Middleton, the chair of the Senate Finance Committee, wants to offer substantial amendments to the bill, Miller said.

Sen. Joan Carter Conway, the chair of the Senate Education, Health and Environmental Affairs Committee, said that she will ask to put the bill back to her committee -- effectively killing it -- if Middleton guts the legislation.

"There is no need to go to war" and pass the controversial measure if it has been amended into a different bill, Conway said. Conway, a gifted vote counter, said she believes the tally will be very close.

Sen. Roy Dyson, a Democrat who hold the No. 2 slot on the Senate environmental panel, predicted that the bill would go "straight to court" if the General Assembly passes it. He said that he remains unclear on what type of development is permitted in each tier.