A struggling economy and the high cost of rental housing in the city of Napa has added  greater pressure on those seeking a rental unit here in the valley.

This has caused more than a few Napans to investigate the ability to construct a second unit on their current home within the city limits.

The goal may be to create space for an adult child returning home, to keep an aging family member on site or to add the investment value of income from a rental unit.

Having recently explored the options available within the unincorporated county, it seemed logical to make a visit to the city planning department to learn a few of the basics  for within the city limits.

 Under Napa section 7.52.020.C you will find the standards for accessory second units (or living quarters) applicable to any residential parcel of land in the city that meets the established requirements.

One accessory second unit of up to 760 square feet is permitted per detached or attached single family home. Larger units are permitted up to 900 square feet if your parcel of land is greater than 20,000 square feet — the size of the unit is scaled to the size of your lot.

 In addition to meeting all of the setback requirements of the primary residence, the second unit will need one parking space per bedroom in addition to the parking required for the main home. The unit can be attached or detached and the owner of the property must occupy either the second unit or the primary residence.

 The driving issues in your ability to place a second unit on your current site are the size of the lot and the ability to meet building setback requirements. The setbacks vary from within different zonings as stated under the code in 17.08.030, but generally the side and rear setbacks range from 15 to 30 feet.

A detached or second-story unit will require planning commission approval and may contain height restrictions and may need to meet design review requirements.

The application fee at the staff review and approval level is $100 and a deposit fee of $750 is required for planning commission approval, if needed. Additional processing costs are likely.

In the end, the process may be worth the effort. A 760-square-foot unit will cost an estimated $152,000 to construct. A like-kind unit currently on the market would rent for $900 per month or $10,800 per year. Prior to operational expenses and tax benefits, this would convert to a 9 percent return on investment on land that you already own.

From a different perspective, the construction could be financed and with a 6 percent interest-only credit line your family members could be living on site in a custom-designed rental unit for $760 per month instead of $900 per month for the equivalent on the open rental market.

The ripple effect of the subprime mortgage crisis has not affected Napa County as severely as some of our neighbors, but tighter mortgage restrictions have decreased the number of home buyers and increased the number of home renters. Constructing a second home is one way to help a family member and increase available housing for our community.

Charles Bogue, a Broker with Coldwell Banker Brokers of the Valley, 1775 Lincoln Ave., Napa CA 94558, can be reached at phone: 258-5221 or e-mail: cbnapa@napanet.net.