The national Rifle Association, which plans to move to Colorado Springs, Colo., next year, has asked for sealed bids for its headquarters on Scott Circle NW. The NRA let it be known that its asking price was about $4 million and attracted a number of lookers. The bids were submitted to W. B. Binswanger, NRA treasurer, who said that they would be opened this weekend at a meeting of the board in Colorado Springs.Also offered - for $500,000 - is an NRA-owned townhouse next door on 16th Street.

The American Speech and Hearing Association sold its headquarters building at 9030 Old Georgetown Rd., Bethesda, for $1.05 million to the National Institutes of Health Federal Credit Union.

In Old Town Alexandria, where Roger Machanic and his Development Resources, Inc., have been active in residential construction, Machanic has seen three former automobile garage sites converted to residential use. One garage was demolished to make way for 25 Tannery Yard townhouses at South St. Asaph and Wilkes streets. Another garage on another corner of the same intersection has been demolished by DRI, which is building 19 condominimum apartments called in a federalist style building called Tannery House. MMachanic was the former contract owner of Green's Stream Furniture Works at South Fairfax and Prince streets, recntly an auto repair shop but now undergoing conversion to 16 luxury condominium apartments by developers Samuel M. Ellsworth, John W. Howell and J. Michael Cramer.

The Washington office of Ivor B. Clark Co., Inc., a mortgage broker firm, announced that it has arranged $20 million in permanent financing for the large new office building that Herbert Blum and Richard Swesnik are developing at 1990 K St. NW. George Hyman Construction Co. is the builder and Vlastimil Koubek the artchitect.

The Washington Suburban Sanitary Commission is focusing its big promotion guns on Camel Week, a water-saving and waste-reduction observance scheduled in Mongtomery and Prince George's counties the week beginning May 22. The idea is to test the ability of suburban Maryland residents to reduce water use as a preparation against a possible water shortage. Most of us are aware that we waste water by leaving the tap run while we brush our teeth, instead of turning it off and on. We can also spray ourselves in the shower and take a water break while latering up and then rinsing off quickly. But do we realize that a car an be washed quite acceptably by using only two half-buckets of water? One slightly soapy to get off the dirt and then another for a rinse. It really works.

Sir Derek Walker-Smith, who is chairman of the National House Building Council in the Unite dKingdom, was ar ecent visitor here. He stopped at the National Housing Center for an exchange of ideas with Richard J. Canavan, who runs the Home Owners Warranty program for NAHB. In England, the warranty program is opeated by the National House Building Council, which is an arm of that nation's equivalent of our savings and loan associations. For that reason, the lenders make warranties a requirement for loans and use the program as a means of avoiding a compulsory government program. It works out much like that here, except that the National Association of Home Builders operates a voluntary HOW program but does not have the clout to obtain compliance in order to get mortgage financing.