There is fear mongering in many forms regarding the state's Accessory Dwelling Unit (ADU) Law and Article #40 - deleting the IIHO.
This was briefly discussed here https://www.amhersttoday.net/post/warrant-article-40-disinformation as False Claim #1, but it warrants further explanation as it seems to be a main argument against Article #40.
What opponents of Article #40 are saying is that without the IIHO, every single development proposed will now have a main house and an ADU. So, every new house built in Amherst will have a one- or two-bedroom structure plus the main house, something like an attached or unattached two-car garage with a one- or two-bedroom apartment above or some type of basement apartment.
The state law for ADUs is:
Section 674:71 Definition
As used in this subdivision, “accessory dwelling unit’’ means a residential living unit that is within or attached to a single-family dwelling, and that provides independent living facilities for one or more persons, including provisions for sleeping, eating, cooking, and sanitation on the same parcel of land as the principal dwelling unit it accompanies.
The two main points for municipalities under RSA 674.72 are:
A municipality that adopts a zoning ordinance pursuant to the authority granted in this chapter shall allow accessory dwelling units as a matter of right or by either conditional use permit
If a 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 a building permit
More information can be found at: https://www.nh.gov/osi/planning/resources/accessory-dwellings.htm and specifically for municipalities at https://www.nhhfa.org/wp-content/uploads/2019/06/ADU_Guide_Municipalities.pdf
Amherst has an ordinance for accessory apartments, Section 3.5 which seems to cover the town, but irrespective of Section 3.5, the state permits ADUs per the second bullet point. There is no mention of controlling ADUs in 4.16 IIHO, so if there is a State statute allowing ADUs, ADUs would be allowed with or without the IIHO.
Any ADU must conform to current requirements established by the current zoning requirements. That means they must meet setbacks from property lines (front, side and back), wetlands, scenic roads, etc. Without the IIHO, any non-conformance would require Zoning Board approval/variance (this is a good thing). The IIHO does nothing to control ADUs on a given property.
Each property must support a septic system for the total number of bedrooms. If there is a 4-bedroom house and there is a proposed 2-bedroom accessory unit, the septic must be able to handle 6 total bedrooms. Some properties would be disqualified right out of the gate. This is independent of the IIHO, and will not change with the removal of the IIHO.
Furthermore, on septic, a lot of times these subdivisions share septic systems. One of the worst things for a septic system is a renter with no care to the condition or status of the system.
Logically, not everyone wants to own a property with an ADU. Not everyone wants to be a landlord and be responsible for someone else living on their property. Builders realize this and will not build a 20-house subdivision with 20 separate ADUs, they won't sell. They will however offer an option, and some people may pay the extra money for that unit, but not everyone!
When RDUs are built, like the one presented in the March 4th Planning Board Meeting, they are generally in-law apartments or for family members. They will unlikely lead to a massive influx traffic or students in the schools.
Summary: Removing the IIHO will actually decrease the overall number of houses irrespective of the ADU law, as the IIHO increases density and overrides existing zoning (which previously regulated over development of a property). Even with an ADU for each new house, the density without IIHO would still be less than currently approved IIHO developments, which are in excess of 200% density.