Manteca, in the last six years, has added more than 100 auxiliary dwelling units.

Known by the bureaucratic shorthand as ADUs, they are either garage conversions into free-standing living quarters or the placement of a smaller house on a residential lot that were called granny flats in the mid-20th century.

The motivation to build them are for two primary reasons.

And examples of both can be found across the street from each other on Raylow Avenue in central Manteca on corner lots.

One family built an ADU for their aging parents.

The other built an ADU for income purposes that is helping pay a chunk of the mortgage on their home.

Former Manteca Councilman Jose Nuno sees the value in ADUs as a way to help address California’s perennial housing shortage.

It is a view shared by policymakers in Sacramento that have reduced hurdles statewide for the construction of ADUs.

Nuno has 17 years of working with a non-profit firm that has successful added less expensive housing the Central Valley.

But he also has firsthand experience. Nuno and wife Gabriela converted their garage into a free-standing ADU for their parents.

Nuno noted there were family, emotional, and practical considerations that made the decision solid.

That said, there are financial advantages for those that build ADUs as it creates income.

The two aforementioned ADUs are on Raylow are ideal for rental property.

They are on corner lots which means they have separate access to the streets for those that reside in them.

Older ADUs that predate 1970 — the city doesn’t have an exact number — are of the granny flat genre that had access from the alley.

Modern subdivisions eliminated alleys, meaning tract homes on the interior of the block would need to share access to reach an ADU in the backyard unless they had an unusual situation air two wide side yards.

That is why he doesn’t expect to ever see Manteca’s elected leaders do what their counterparts in Berkeley recently did — make it legal to sell ADUs as condos.

One of the big cost savings in ADU construction besides a number of fees being reduced — or eliminated if it is less than 500 square feet — is the fact they are hooked to existing sewer and water meaning they don’t need costly separate connections.

Most, if not all, ADUs in Berkeley are either garage conversions or take advantage of state laws that allows subdividing homes in existing houses that meet separate requirements into essentially free-standing apartments complete with kitchens and bathrooms.

Besides the messy issue of two separate owners as opposed to a renter and owner on the same utility bill, if the ADU requires the same driveway as the main house to access it can create issues as opposed to a landlord-tenant relationship.

That said, Nuno believes the City of Manteca should do whatever it can to spark more interest in building ADUs.

The city already offers reduced fees as incentives and even has several basic boilerplate plans people can use.

Nuno noted affordable housing should not be driven by the concept of home ownership. The goal, he noted, is to generate more housing that more people can afford to live in.

Making homes more affordable for more people to purchase not only has a higher threshold but is a much more costly propositions for households to pull off.

That said, he can see how ADUs could help upgrade older neighborhoods and benefit aging homeowners that could use additional income.

In such cases, building a free-standing ADU or a complete garage conversion gives such households rental property.

It also gives them a different twist on “aging in place.”

Such households could build the ADU to not just downsize but to design it in a manner than bathrooms are more suitable to older residents.

Not only would they remain in their same neighborhoods and continue to enjoy the same community ties, but renting out the “main home” and living in the ADU is likely to provide them with an even higher rental income.

To contact Dennis Wyatt, email dwyatt@mantecabulletin.com