WITH ALL THE thousands of saltwater addicts migrating to the shore every weekend, the waterfront -- waterfronts, actually -- are Washington's forgotten treasures. The Potomac and Anacostia rivers scrawl a huge affirmative Y through the hot heart of town, with the canal close at hand; and Rock Creek, with its plentiful picnic spots, runs right down the middle.

The redevelopment of the Georgetown waterfront as a restaurant complex has been a major boon to downtowners and commuters, and offers a view sweeping enough to make it worth testing the waters at even the more stiff-necked (or stiff-billed) sites. Even if they're not total successes, they're worth a stop.

When New York restaurateur Warner LeRoy "set" Potomac into Washington Harbour a few years ago, he seemed to have mistaken K Street for Sunset Boulevard. Overdressed, dripping with artificial gems and with a perverse childishness (represented only partly by the gilt-brushed train set), Potomac was like Norma Desmond in a town more attuned to Connie Chung.

Well, thanks to the folks from America, what's now called Sequoia has been not so much redecorated as de-decorated -- stripped of fripperies and only mildly dangling with models of ships, from the lowliest tug and fishing scow to the grandiose liner at the entrance. It's now a much more comfortable (albeit still a bit self-conscious) place to have cocktails, especially at the outdoor tables, which look south over the boat ramp and (in spring) the daffodil fields.

The lounge itself, which is upstairs, has a sweeping view, too, though somewhat obstructed by the roofline; on the other hand, being indoors eliminates the main waterfront drawback -- the roaring of the jets overhead. The prestige table of the year is in the glass curve at the north end of the bar -- it seats 12 and sees all. Sequoia now carries six beers on tap: two microbrews, Sam Adams and Anchor Steam; two Pennsylvania regional brews, Rolling Rock and Yuengling; Bass and Coors Light. The tumblers, at least, are still Hollywood-oversized, and at about $3.25 apiece in line with the average tavern.

A more relaxed (i.e., more cash than credit card) atmosphere rules next door at Tony & Joe's, which has stretched out its Washington Harbour restaurant into a waterside cafe. This is a wonderful place to sit at sunset, between the river and the Harbour's spray-blowing fountain plumes; there's a special perverse comfort in watching the admirable exertions of a passing rowing crew from beneath an umbrella.

Of course, in Georgetown, summer livin' may be easy, but it's never free. Tony & Joe's summer special, the "cool blue margarita," is as good as advertised -- served in a 12-ounce tumbler, the slush held to a straw-pulling density, some spiritual force yet detectable and the flavor neither cloying nor with that peculiar tongue-twisting artificial-citrus aftertaste that haunts so many premixed margies these days. On the other hand, at $5 a round, they ought to be good. Presumably the tab is really about $4.50 and tax, so at least you don't have to fumble for change; but that's still a hefty bit above most local bars, especially at what used to be called happy hour.

On the other side of Sequoia, across the fountain from Tony & Joe's, is Hisago, where you can try the Japanese version of a cooler.

Few things are more appealing on a hot summer evening than sushi, but sake drinkers may find the traditional warm-weather version -- sake over ice -- less gratifying. Somehow, the flavor turns thin and tendentious, as if unwilling to be treated so rudely.

But there is a sake brewed especially to be served cold, a broader, more herbal-scented sake that has some of the characteristics of a vodka. Called Tarusake -- "taru" is a keg or cask -- it's brewed by Kiku-Masamune, purveyors (as the Russian vodka folks used to say) to the Imperial Household. It comes, at least in the United States, in a small bottle, about the same size as the vase hot sake is usually served in, but its earthy aroma comes from its having been aged in cedar; if you've ever drunk hot sake from a ma'su, one of those small spruce boxes, you have the idea.

Tarusake is also available at Tako in Bethesda, which struggled for many months to sort through the importation red tape. There the bottle is delivered in a personal-sized ice bucket designed to look like those straw-wrapped sake casks, with chilled Scandanavian-style glasses instead of the usual porcelain tumblers.

On the other hand, you can do the waterfront picnic European style; stop into Cafe Rose (inside the Washington Harbour arcade) and pick up one of their indulgent pastries and an espresso to go, and walk over to the landing. The cafe's open until midnight every day except Monday, so you can even do the lights-on-the-water number.

15 MINS. LIVE: Downtown's 15 Mins. has added live music on the weekends, as promised; and in fact is picking up a little of the roots 'n' R&B slack from the late, lamented Twist & Shout. Friday and Saturday, and next weekend as well, the headliner is Ernie Locke, whom club partner and Glenn Danzig lookalike Joe Englert describes as a "psychedelic harp player from Kansas City." Covers in the $5 range; 408-1855.

Even more intriguingly, 15 Mins. and Pink & Black Promotions this weekend kick off the "Sunday Night Barn Dance," full-fledged theme nights featuring double bills of local and national bands specializing in rockabilly, traditional country, bluegrass and roots rock. Shows are relatively early (9 to 11) to meet the subway deadline and ease the Monday morning blues; those who want to stay later can enjoy vintage TV and movie clips of the C&W&R&R greats, along with videos of new-trad artists. There's a two-tier cover, $4 from 8 till 9 and $6 thereafter, which should improve the quality of the opening set for both performers and audience; although this Sunday's kickoff show, featuring the Reluctant Playboys (the former P&Bs themselves), is an introductory freebie. Next Sunday the Barnstormers from New York double up with the Snarly Yowls from Frederick. OOPS!: We dropped a word in the review of Sisson's brewpub in Baltimore last week. The stout does not have a bitter aftertaste. However, it apparently does weaken the brain. Sorry, guys.