Once again, California is leading the way for solar hot water with a new solar thermal incentive, this time for low-income single-family properties and multi-family dwellings.

Regular readers to the Free Hot Water blog are probably familiar with California’s CSI Thermal rebate program that was introduced 2010. It’s perhaps the most generous solar water heating rebate program in the United States, offering up to $500,000 for commercial properties and up to $1,875 for individual homeowners.

Now, California’s Public Utility Commission (PUC) has introduced another incentive that targets low-income housing and individuals. Called “The CSI-Thermal Low-Income Program”, the goal is pretty self-explanatory.

In terms of numbers, the low-income program provides customers of Pacific Gas and Electric Company (PG&E), San Diego Gas & Electric (SDG&E), and Southern California Gas Company (SoCalGas) with up to $3,750 in rebates—double the regular rebate.

For multi-family dwellings, such as apartment buildings, nursing homes, and assisted living homes, owners can receive up to $500,000. The top figure differs from the regular program in that owners will receive a 50% higher rebate for the natural gas displaced by the solar system.

Therefore, while the maximum amount is the same, a 10 collector solar thermal system under the low-income CSI thermal program is going to receive up to $19.23 per Therm displaced, whereas the same 10 collectors will receive up to $12.82 per Therm displaced in the regular CSI Thermal program.

Those are the highest rates. As the program grows and more installations come on line, the rebate amount will decrease for both programs, and, in theory, so will the price of installing solar water heating systems. (You can keep track for the current CSI Thermal rebate level here.)

Of course, there are substantial requirements for properties to qualify under the CSI Thermal low-income program. You can download a summary of the eligibility requirements here.

On top of the new rebate, owners of low-income rental properties—whether single family rentals or mult-family—are also eligible for the Federal government’s 30% investment tax credit (ITC).

While the application process may be complicated, solar thermal systems are not. To help simplify the installation process even more, Free Hot Water has created multiple pre-engineered solar thermal systems for both homes and multi-family systems that that will meet all of California’s CSI thermal equipment standards.

Combined, these Federal and state financial incentives should help to inspire more solar hot water installations in California, which still lags behind PV. In fact, the traditional CSI Thermal program began in the fall of 2010, and the program still hasn’t burned through its top rebate step. So, there’s still plenty of work to do to get the solar hot water word out.