Manteca is going up — and increasing density — in older neighborhoods.

*Several older houses on Stewart Street just off the eastern edge of downtown were torn down and now a three-story, 12-unit apartment complex is under construction.

*An old tear-down cottage that had fallen into disrepair the 600 block of Center Street on a narrow lot is now being replaced with a two-story duplex.

*A vacant parcel off of the 900 block of West Alameda is now being turned into 10 duplexes.

*There has been an upswing in building activity involving so-called “granny flats” —standalone auxiliary housing units.

*In the past two years there have been a small but growing number of smaller and aging houses dating back to the 1930s — such as two near Manteca High — that have been replaced with larger new homes.

Investment in new housing in the city’s has been climbing in recent years.

Fueling the trend besides growth is the fact vacant land and parcels that are under-utilized with existing housing pencil out in the changing market to be viable projects.

Infill housing is also closer to shopping, restaurants, services, often schools, and pubic transportation than newer tract developments. Much of the central district consists of what planners call “walkable” neighborhoods.

The new homes — free-standing, duplexes, and apartment units — command higher rent and selling prices but they are still below the average cost by 10 to 20 percent of projects in newer section of the city.

The driving force behind that is the fact the basic infrastructure is already in place — sewer, water and storm main  lines, streets, and even phone, cable, electric, and natural gas service.

Not having to extend trunk lines and such to serve a new housing unit thanks to the infrastructure backbone being in place helps reduce construction costs upfront.

At the same time adding additional housing units on existing lots that is feasible in much of central Manteca as well as on many lots developed after 2000 south of the120 Bypass can be done at a lower cost in terms of impact fees.

Impact fees can add tens of thousands of dollars to the cost of building a house.

There are several impact fees that are not collected in Manteca on auxiliary dwelling units 750 square feet or less in a bid to encourage more ADUs.  

That helps ADU projects pencil out.

And if the ADU is 500 square feet or less the builder is also exempted from paying school impact fees to further reduce development costs.

The ADU is allowed to have a maximum square footage of 850 square feet in a studio-style layout, a maximum of 1,000 square feet for a one bedroom dwelling or 1,200 square feet  for a handicapped accessible home. They cannot be higher than 16 feet.

No additional off-street parking will be required for an ADU. They also must have an independent exterior entrance.

There was a time when so-called “granny flats” — small secondary dwelling units accessed from paved alleys or behind existing homes — provided Manteca with a supply of affordable housing. They lost popularity as tract development took over and many cities made then virtually impossible to build.

The current state movement that requires allowing garages conversions done to code, ADUs being built whether they are free-standing or added to and existing house, and allowing the conversion of single family homes into multiple family residences are all aimed at squeezing the most out of existing developed areas to help address California’s chronic housing shortage.

ADUs must be allowed in all zoning districts where residential uses are permitted. Local discretion for location of ADUs may be based only on the adequacy of water and sewer services, traffic circulation, and public safety considerations.

The dwelling units may be rented separately from the primary residence but may not be sold or otherwise conveyed separately from the primary residence.

To contact Dennis Wyatt, email dwyatt@mantecabulletin.com