ADUs
Aug 14th, 2024 by Jonell O'Day
Zoom Meeting in lieu of the IVA scheduled Board meeting. 4/18/2024 – 6 pm
SUBJECT; ADUs in Marin – ADUMarin.org, aducenter.org (they appear to be the same site)
Narrator; Scott Johnson – Scott@aducenter.org
ADU Definition; An accessory dwelling unit, or ADU, is a unit with a full kitchen and
bathroom that is accessory to residential. Also called a granny unit or second unit, it can be
on a property with a home or apartment building. JADU (Jr. ADU – 150 to 220 sf studio unit).
SUMMARY for Indian Valley (only)
During the Q&A the question of “areas with septic systems” came up – we will start there
because it relates to Indian Valley.
• If a residential property has a septic system, PRIOR to seeking a permit, the septic
system should be checked to ensure it is sufficient for additional living area/bath.
• Typically, a permit inquiry would be the starting point. However, if there is a septic
system, a permit would not be possible if the property’s septic is not adequate for
additional living area/bath.
• The same would be true if the only water is from a private well – the well would need
to be evaluated to see if it is sufficient for additional living area.
• Permit & Development fees range from $5,000 to $10,000 depending on the size of
the ADU or JADU. There are different classes of ADUs; Small, Median and Large
(depending on size and bedrooms), the size dictates the Permit/Development cost.
• Sizes; 150 to 1200 sf, height; 16 to 18 ft.
• In the County, two units can be built at 800 sf or less – IF all planning codes are met.
~Planning codes; setbacks, etc. There is A LOT to consider before an ADU can
be permitted.
• There may be as much as $10,000 funding by the county if the landowner commits
to having the ADU be “low-income housing”.
• Compost toilets are not permitted.
• Short term rentals are not permitted – Airbnb, etc.
• Lot splits are difficult – if you want to split a lot to build an additional unit.
• Consult your HO insurance company to see if an ADU would be covered.
• Owners may need a business license.
• They discussed attached or detached units, different sizes and height restrictions.
• The number of ADUs on SFR (single family resident) property depends on the lot
size, utilities/septic/water, topography and building codes.
RESOURCES; ADUMarin.org and ADUcenter.org appear to be very helpful with cost, rents, value, plans
and feasibility – contact Scott Johnson at Scott@ADUcenter.org if you want to understand more.
