TIVERTON — A Newport County Superior Court has ruled that Tiverton Yacht Club’s planned new septic system amounts to an increase in the size of a non-conforming use, and may not be installed.

The decision by Judge Melanie Thunberg came as a surprise to yacht club officials, and brings construction of the new system to a halt. A backhoe at the club’s property on Riverside Drive was about to start digging, but will now have to be removed, said Wayne Karzenski, the club’s commodore.

“It’s so bizarre, where she’s making DEM [Department of Environmental Management] policy basically,” Mr. Karzenski said.

He said that the judge limited the club to a septic system that had the same capacity as the one installed in 1987, which was 525 gallons. The new one, approved by DEM, would have had a capacity of 1,615 gallons and accommodates the current activity levels of the club, including the swimming pool, activities Mr. Karzenski said the judge had approved.

Mr. Karzenski said that when the club was preparing to install a 525 gallon system a few years back, the neighbors complained to DEM, saying that it wasn’t large enough to meet the club’s needs, and DEM told the club to make it larger. Now the neighbors are asking for a smaller system.

The new septic would have been in place within a couple of months, Mr. Karzenski said. “Now we’re trying to figure out where we go from here.”