In January 1928, Purity established its first Mill Valley grocery store at No. 2 Corte Madera Ave. It was one of 92 such stores in northern California. In October, the store moved to larger quarters in the O’Shaughnessy Block across the street. The store added an up-to-date meat department. “The large meat box and display counters are both equipped with Frigidaire units to keep the meats in perfect condition.” In those days, clerks behind counters served customers by retrieving goods from shelves, sometimes floor to ceiling. In 1939, the store was enlarged and modernized for “self-service, the finest and newest technique in food merchandising. Attractive new island counters were installed. Housewives can browse through the ample shelves, filling their baskets, and then bring them to the large new checking counter, where trained helpers take the goods, check it, place it in larger sacks, and total the purchase.” In 1956, the Purity Store moved to a new site on the corner of East Blithedale and Camino Alto and became a super market. The $250,000 structure covered 14,700 square feet. The parking lot had a 137-car capacity. The huge new market followed the familiar simple architectural treatment, a Quonset shape that became identified with Purity Stores everywhere.