Regulatory Requirements for Creating an ADU:

Zoning:
​The zoning ordinance limits the location of entrance doors and the size of the ADU. Please review all the other requirements, such as setbacks, size, height, etc.
​Construction:
A building permit is required to build an ADU. Depending on the scope of work, your project will most likely also require electrical, fire protection (sprinklers), mechanical, right-of-way, and drainage permits issued by DPS. Fees for permits and inspections can add to your costs.
Fire Protection:
​​If you plan to add a sprinkler system, DPS will issue a fire protection permit. What modifications are required to accommodate the sprinkler installations, such as the correct water pipe size and meter?
Water and Gas:
​The same applies to fire protection; if you plan to add a water and gas pipeline system, you must follow the water modification requirements.
Drainage:
​For properties under 15,000 square feet without an approved stormwater management plan, new construction or additions require a drainage plan. This plan must detail measures to control and safely manage runoff caused by the project.
Land Development:
A sediment control permit is required for land disturbances of 5,000 square feet or more or projects involving 100 cubic yards of earth movement. For ADUs on septic systems, a new septic reserve area must be established, requiring soil testing (water table and percolation tests) and a new septic system permit. If successful, a final plan must be submitted for approval, after which the septic permit is issued, making the building permit eligible for approval. In some cases, a separate well may also be required.
Covenants and Deed Restrictions:
​Many of the subdivisions and developments in other counties have private deed restrictions and covenants regulating the construction of decks beyond the limitations contained in County Ordinances. These amount to contractual agreements and thus the County does not enforce covenants and deed restrictions.
Design and Space Planning:
You have to know if you need a full kitchen, bathroom, or private entrance. Optimize storage and layout for a small space in a room. The materials must be durable and cost-effective enough to withstand the test of time.
Construction Timeline and Disruptions:
Building an ADU can take several months, depending on the availability of permits, materials, and labor. Be prepared for noise, temporary utility disruptions, and limited yard access during construction.