Board of Health Passes Temporary Moratorium On Septic Variance Requests

The Board of Health unanimously passed a moratorium on septic variance requests in nitrogen-sensitive areas during its meeting on Thursday, temporarily limiting the ability of homeowners to add additional bedrooms to some buildings on Nantucket.

“Although we are obligated to consider each variance application on its own individual merits, I believe that it is in the public interest to impose a temporary moratorium for the purpose of enabling the board to review the necessary information and scientific developments so that we can make fully informed decisions,” Board of Health chair Malcolm MacNab said.

Regulations limit the number of bedrooms homeowners are allowed to have based on the square footage of the building. One of the reasons for this restriction is to limit the amount of nitrogen that enters the surrounding environment. Nitrogen, which is found in significant quantities in human waste, is an important nutrient for plants but can cause environmental harm when concentrations get too high. Many invasive species are held in check by limited nitrogen supplies, as they can only grow as much as the available nutrients allow. When nitrogen availability increases, these species often experience a surge in growth, choking out native plants and animals. This is particularly pronounced in aquatic and wetland ecosystems.

However, applicants can ask for a variance from the regulations for more bedrooms. Historically, the Board of Health has generally granted these variances when applicants plan to switch from a conventional septic system to an innovative/alternative, or IA system. IA systems are believed to reduce the amount of nitrogen that enters the environment, as they treat sewage more effectively and thus contain more nitrogen. In theory, even with the allowance for increased bedrooms, switching to an IA system will reduce the amount of nitrogen that enters the environment.

But several members expressed concern Thursday that the existing policies are out of date and do not reflect the most recent science, which raises questions about whether IA systems reduce nitrogen loading when additional bedrooms are permitted.

“Recently, it has been suggested that increasing the number of bedrooms on a property can be more detrimental to the health and environment of the island and that the benefits of an IA system do not sufficiently offset that harm,” MacNab said. “Since the Board adopted its IA system regulations several years ago, there have been new developments in IA system technology and scientific research concerning their effectiveness.”

The environmental impact of increased nitrogen was not the only concern raised by Board of Health members.

“That’s two more people for every bedroom. The pressure on our hospital, on our fire department, on our roads, on our water,” Board of Health member Merideth Lepore said. “There’s not just one thing to look at, so I think it’s a really good idea.”

The moratorium will allow the Board of Health time to review the existing science, consult with experts, and ensure that their policies conform to best practices. It will last until the Board of Health meeting on September 18th. In the meantime, existing applications for variances filed before the moratorium legally have to be heard, but the Board of Health can choose to reject them without prejudice, which would allow the homeowners to bring them back before the board after the moratorium expires.

The moratorium does not apply to applications to replace or upgrade failed systems, as long as there is no increase in sewage flow, nor does it apply to systems that do not require a variance.

At Thursday’s meeting, the Board of Health voted 3-1 to grant three septic variance requests despite the moratorium, with Lepore in the minority.