Home mortgage interest rates in the Washington area have stopped climbing and in some cases have started back down, local lenders reported this week.

Most new mortgages in the District of Columbia and Virginia carry rates of 10 1/2 to 10 3/4 percent including discount points paid by buyers and sellers.

But two large savings and loan associations confirmed yesterday that they have recently lowered their rates by 1/8 to 1/2 a percentage point.

Savings and loans in Maryland are not making mortgage loans because the state usury law sets a maximum rate of 10 percent, and market rates now are higher than that.

Lenders said rates went up in December because there was a shortage of lendable funds. Savings are increasing now, they said, and loan demand has decreased, so rates are coming down.

"Money now is chasing deals," said one S&L executive.

On mortgages for 75 percent of the value of a house -- in other words, a 25 percent down payment -- loans are being made in the District of Columbia and Virginia at 10 1/4 percent, with one discount point paid by both the seller and the buyer, making the effective yeild 10 1/2 percent to the lender.