YOU DON'T have room for a spa - physically or mentally?

It costs too much money, and besides, who knows how much longer you'll be living in that apartment/house/dump. What happens when you move?

This year home manufactures, flushed with excitment, are introducing a flood of portable gadgets and accessories guaranteed to turn your ordinary, everday bathroom into a total body-care center. Here are a few home improvements you can take with you:

The Nordic Spa, a dry heat single-occupant fiberglass portable spa, plugs into any outlet. You remember the cartoons - it's the moveable model with the person's head sticking out the top and sells for $590. A standard steam cabinet, which disassembles into four-foot sections for easy packing, sells for $538. Both available at American Comfort Corp. in Rockville

George Washington never traveled without one. A cherry tree? Guess again - a portable bidet. The Rusco Bidet replaces your present toilet seat with automatic lever control warmwater wash, for that "shower fresh feeling." Piugs into household outlet; no plumbing required. Available through Hammacher-Schlemmer for $350.

The way we whir . . . Relieve those aches and pains with a cordless electric rechargeable Whirpoool Bath that fits into any standard tub and comes with attachments for localized messages. $399.95 through Hammacher-Schlemmer, 147 E. 57th St., New York, N.Y. 10022.

Have fog, will travel . . . Instant Spa, the portable bathroom accessory for under $50, turns your ordinary shower into a warm, misty steam bath. Coming soon to area stores, including Camalier and Buckley.

The Foot Fixer, Clairel's new foot-care system, doesn't have to be nailed down. Bathe your tired tootsies, then switch the dial for heat and massage. Coming soon to area stores.

Bathroom of champions . . . bath accessories selected by the U.S. Olympic Committee, including Position Dial Massage Showerhead, portable whirpool baths from $79.95 to $199.95, hand-held heat massagers from $9.95 to $49.95 and the Deep Heat Back Massager.

They'll never get you out of the bathroom now.