An accessory dwelling unit (ADU) is a great way to add more space and functionality to your property. However, you don’t have carte blanche when you build an ADU. There are general California-wide requirements for ADUs and specific ones in Fremont that you will need to follow. One sticking point is often the bathroom: do you need one for your ADU in Fremont or not? We’ll answer your question below.

Fremont ADU Bathroom Requirements

The Fremont criteria for accessory dwelling units does not state outright that you need a bathroom. However, you still will in most circumstances. The California Residential Code mandates that all ADUs need a kitchen and a bathroom, and the Fremont-specific rules cannot override the California Residential Code.

What does the Fremont code say? It states that the ADU must have “permanent provisions for living, sleeping, eating, cooking, and sanitation on the same parcel as the … dwelling.”This means that ADUs, whether attached or detached, must have their own bathroom space on the property. They may also need a kitchenette, and an HVAC system for heating and cooling, and other essential elements you would expect in a home.

Junior Accessory Dwelling Units

Interested in building an accessory dwelling unit but don’t quite have the space for a bathroom or other essential elements of an ADU? The Fremont guidelines allow homeowners to build junior accessory dwelling units (JADUs). These units are within the walls of a home or within the existing attached garage. They must be less than 500 square feet, or they are considered normal ADUs.

JADUs do not need to have a private bathroom, so long as the person renting the space has access to a full bathroom in the main residence.

JADUs can also be less expensive to construct because they avoid some of the other costly elements of an ADU. For example, they do not need firewalls, and they do not need noise insulation. They do not need off-street parking. While they do need some kind of kitchen, the size can be small, relative to the unit’s small size.

A JADU does need:

  • An exterior entrance on the side or rear of the house
  • A kitchen with a food prep counter, appliances and cooking facility
  • Smoke alarms and carbon monoxide detectors

Other ADU Requirements

If you decide to dive into building a full accessory dwelling unit, it will need more than just a bathroom. There are many other requirements for these units, including:

  • A permanent foundation
  • Smoke alarms and carbon monoxide detectors
  • Parking, in most circumstances
  • A kitchen

Of course, you may want to add other accessory dwelling unit amenities to make the space more appealing.

There are also many different restrictions placed on accessory dwelling units in Fremont. They have lot coverage, floor area ratio and open space requirements. However, you can get around many of these requirements if you build a California-recognized special class of ADU. These are detached, up to 800 square feet in size and need to have four-foot side and rear setbacks.

Talk to the experts about how to interpret building code for your own accessory dwelling unit. You can also visit the city of Fremont’s ADU fact sheet to see the current codes and requirements, which are always subject to change.