Creates tax breaks to grow affordable housing. Property owned or used by social housing agencies gets a full property tax exemption when at least half the units are rented to people earning 80% or less of local median income and the project uses public housing funds; otherwise a partial break per eligible unit. Sales to these agencies for low-income housing avoid the state real estate sales tax with a 15-year recorded promise to keep homes affordable. Temporary breaks allowed during renovation. Likely more affordable rentals, but lower local tax revenue.