The information contained in this article is not intended as legal advice and may no longer be accurate due to changes in the law. Consult NHMA's legal services or your municipal attorney.
With the recent passage of House Bill 577, which substantially amends RSA 674:71 to :73 related to Accessory Dwelling Units, many municipalities are scrambling to figure out how to deal with these changes. Since the new law is already in effect, many municipalities are already seeing an influx of building applications for ADU’s. This is particularly confusing since many local ordinances may now find themselves in conflict with the current state of the law. NHMA has produced a guidance document on how to navigate this complicated landscape, which can be found on our website, but this article will address some of the more common and some of the more unique questions that have been raised over the last few weeks.
Q. What are the new requirements for municipalities under the law?
A. A municipality that adopts a zoning ordinance shall allow accessory dwelling units in all zoning districts that permit single-family dwellings. One accessory dwelling unit, which may be either attached or detached, shall be allowed as a matter of right, and municipalities may no longer require either a conditional use permit or special exception for an ADU. This is a big change from the previous language of the statute which only required municipalities to allow attached ADU’s, and left room for local regulation via conditional use permits or special exceptions.
Q. What if my municipality does not have a zoning ordinance or does not address ADU’s?
A. If your zoning ordinance contains no provisions pertaining to accessory dwelling units, then one accessory dwelling unit shall be deemed a permitted accessory use, as a matter of right, to any single-family dwelling in the municipality, and no municipal permits or conditions shall be required other than building permits, if required by statute.
Q. My zoning ordinance has conditions related to ADU’s that are in conflict to the new law. How do we reconcile the difference between the current state of our zoning ordinance and the current state of the law when we can’t update our ordinance until the next town meeting?
A. Many ordinances that require conditional use permits or special exceptions are now unenforceable given the changes to the law. Municipalities are no longer able to enforce those provisions as of July 1, 2025. Therefore, you must abide by the new law as opposed to conflicting provisions in your ordinance. One option could be to provide a supplement or asterisk next to the unenforceable portion of your ordinance explaining the new requirements. It should be clear to residents what options are now available.
Q. Do we need to call a special town meeting to update our ordinances? Are we legally required to update our ordinance?
A. No, you do not need to call a special town meeting to update your ordinance. You can wait until your next town meeting to amend your ordinance so that it is in compliance with state law. However, you should make it clear in the interim what provisions of your ordinance are enforceable and which ones are not. The change to the law does not strictly require you to update your ordinance, but due to preemption, the state law is going to trump any conflicting local regulation. If you leave a conflicting regulation on the books it can create confusion both for local officials and for residents. This could lead to violations of the state law and possible lawsuits against the municipality. Therefore, it is probably a good idea to amend your local ordinances to be in compliance with state law.
Q. My current ordinance limits ADU’s to not more than 50% of the gross floor area of the primary unit. What if the primary dwelling is fairly small and 50% is less than 750 square feet?
A. A provision such as this would probably not be enforceable. Your zoning ordinance may still establish size limits for ADU’s, but it may not limit an ADU to less than 750 square feet. Therefore, while you could have a provision that restricts ADU size to no more than 50% of the gross floor area of the primary unit, you would need an additional provision which capped that limitation at no less than 750 square feet.
Q. What if our current ordinance limits ADU square footage to 750 square feet and we want to expand that provision. The new law allows ADU’s to be up to 950 square feet or more as authorized by the municipality. Does this mean that we can immediately start allowing ADU’s larger than 750 square feet?
A. No, while the amendment to the law will trump any conflicting provisions of your local ordinances, you will still need to abide by any local regulations that are not in conflict with the state law. Therefore, if your current ordinance limits ADU’s to a certain size, as long as it is not less than 750 square feet, you must continue to abide by that requirement until you amend your ordinance at the next town meeting. While it may feel like this statutory change has opened the door to amending or altering your ordinance immediately, as opposed to going through the town meeting process, this only applies to provisions which are now legally unenforceable under the current state of the law. All other optional provisions, or provisions which are still in compliance with the current state of the law will need to be updated via the usual process and procedures.
Q. Our current zoning ordinance contains a provision that an approved ADU cannot be used as a short-term rental and be rented for transient occupancies for periods of less than seven days. Can a municipality impose a short-term rental restriction on an ADU that is permitted under HB 577?
A. If the town’s zoning ordinance has no limitation on short term rental uses of land pertaining to single-family zoning uses, then an ADU cannot be subject to any short term rental use limitations. If, on the other hand, the town has existing short term rental use limitations that are applicable to single-family uses, those same existing limitations would apply to an ADU.