The Salt Lake County offices of United Savings Bank/Western Mortgage Loan Corp., made 401 mortgage loans during the third quarter of 1990, a 13 percent increase from the 355 loans in the same period a year ago.

The dollar volume increased from $22.3 million to $27.3 million, a 22 percent increase. It is the third consecutive quarterly increase in mortgage loans in 1990.In the first three quarters of the year, the companies made 1,038 loans, a 37 percent increase over the 755 loans made in the first nine months of 1989. The dollar volume increased 46 percent from $48.9 million in 1989 to $71.4 million this year.

Mark Garner, vice president of residential lending, said the figures mean United Savings/Western Mortgage had 10 percent of the Salt Lake County market share, a 1.5 percent increase over last year.

"It is rewarding to see growth in both market share and overall market volume. We are pleased with our performance so far this year and anticipate continued growth through the end of the year and in 1991," Garner said.

Dollar volume for all of United Savings' Utah offices increased 8 percent in the third quarter of 1990 to $45.3 million from $41.7 million in the same period a year ago.