On Capitol Hill, it is called "the contemporary house" - a real distinction where the prevailing style might be best described as Late Nostalgia.

On the other hand, unlike some contemporary houses in traditional areas, the house at 316 9th St. SE has always been well received by its carriage-lantern neighbors. Also, it may well be the only house built in 1966 to have received a restoration award plaque in 1967.

The owner and architect, Thomas Baxter Burke Simmons, likes the plaque because he thinks the Capitol Hill Restoration Society showed it values good design of this century as well as the last.

Simmons, his wife Angela Solima Simmons, a geneticist, and their son Marco, 13, like their place in life because it offers them, through miniaturization as intricate as a solid-state circuit, all the homey pleasures, including flower and vegetable gardens and a swimming pool.

Furthermore, in the tight 45-by-116-foot space, Simmons has also managed to tuck in two profitable rental units - almost as essential to a house as a roof in this day of high taxes and utilities costs. And in a neat bit of now-you-see-it, now-you-don't, Simmons has also contrived a suit of offices for himself. All have private entrances. There is even that great rarity, a garage.

Though Simmons, rightly, likes to think the house belongs only to its own time and place, it does have rather the feeling of a Mediterranean villa, suggested by its gates, its sunny-yellow smooth stucco, and the wood grilles that shield the windows from the street. The only concession to its Victorian neighbors is its height.

From the street you see a small patch of ivy and shrubs. At the building line, which on 9th Street is quite close to the sidewalk, is a wall with modern iron gates (by Northeast Iron Co.) on either side, and in between is an opening which works like a window. The tin roof is a Derusto brand red/brown paint against the yellow stucco (over concrete block).

The visitor, walking through the left gate, is in a charming entry court with pleasant planting including a tree that casts leafy shadows on the smooth stucco wall. If you go straight ahead, you enter the one-bedroom rental unit. If you climb the steps, you arrive at the Simmonses' own quarters.

"I like steps," Simmons said. "Changing levels change the vistas and give interest to a house."

Actually, the Simmons building is two houses, built ten years apart. The old section has a rental apartment on the first floor, Simmons' living room, study with bath, kitchen and dining room on the second floor, a child's bedroom an sitting room on the third floor. The new house has Simmons' office on the first floor; a rental apartment with a living room, kitchen and bedroom on the second floor. In the new wing on the third floor are two bedrooms, with a locked door between. One opens to the tenant's staircase, the other opens into the Simmonses' original house, giving them a new master bedroom. The third-floor door is the only connection between the houses.

Inside the older house is the living room, to the left the study with its Simmonsbuilt desk and storage units; a bath; and the kitchen with breakfast area. A few steps up is the dining area, a story and a half high, open to the balcony above.

A sliding shoji screen slides across glass doors leading to the deck. In the daytime, the diners can watch the play of light on the pool.

The living room and dining balcony, in deference - Simmons said - to his Italian-born wife, have a rich traditional look compounded of deeply colored oriental rugs, red-, black- and gold-painted English china, a big circular super-pointillism painting in red, a palisander dining table made in England and bought in Italy, with matching Italian Empire chairs, and a handsome display of plants. One plant is placed on a pedestal which in other locations would be a sewer pipe. The clay pipe works wlll because its top forms a basin for the flower pot.

Upstairs are Marco's room, a bath and the laundry room to the north, a family sitting room in the middle, and to the far south, a romantic master bedroom.

"I designed our new room while laid up with an ankle I broke ice skating," explained Simmons.

The bed has its own three-sided low wall, making a headboard. Above is a domed skylight to the balcony through sliding glass doors works like a greenhouse because of the slanting glass roof. The floor here is marble, from Ben Troiano in Beltsville, bought and laid in large sections because that's cheaper.

A walk-in clothes closet and bath finish the suite.

To reach the new house's rental apartment you come in through the gate at the right on the street level. Once you pass through the brick-paved entry court there, separated by a wall from the Simmonses' own court to the left, you can go in by climbing a wood staircase to the front door, or you can walk through a passageway to a circular staircase in the middle of the new addition.

Either way, you arrive at the living room, with bar, kitchen and bedroom on the second floor. The third-floor bedroom is reached by a staircase which has a small landing with a couch tucked in.

If, instead of going up the stairs, you stay on the first level, you arrive at Simmons' architect office.

The drafting room, like the new master bedroom, is much lighter, brighter and cleaner-lined than the 1966 house, reflecting changing design taste. The furniture here, three drafting tables and storage cabinets, is mostly painted white. Because the lot slopes, the drafting room, like the apartment on the same level, under the main house, is sunk into the ground to about knee level. The glass windows (casements by Hope, sliding-glass black anodized doors by Arcadia) meet the ground on the outside. The glass offers almost the feeling of being outside.

On the same level, in the conference room, often used by the Capitol Hill Restoration Society (Simmons is president), a pair of barnsized doors have a circular window with a wood muntin like outstretched arms. Simmons calls it his Dali window. Marco, who is quite a ceramist, designed the stained-glass window on an upper level.

Touches of red - on a chair, in a poster, in fabric used above the built-in counter - help to relieve the white.

The back garden, which can be reached by the passageway from the street, through the new section, is planned to serve all three units. The pool occupies most of two lots, with a fine, formal toolshed and grape arbor at its end. Mrs. Simmons is espaliering a fig tree on the wall facing south and growing vegetables and flowers mixed with great success. Camellias are planted on the wall facing north.

The Simmons bought their first two lots, totaling 30 by 116 feet, in 1963 fr $11,000 after looking all over Washington for a vacant, close-in lot. They bought the 15-by-116-foot third lot for $12,000, a larger price for a lot half the size of the original purchase. Similar lots on the Hill now go for $35,000.

They didn't build for a while, waiting for the area to improve, in the meantime living in New York. In 1966, when Simmons had moved to a job with the firm of Keyes, Lethbridge & Condon architects, they built the first house, doing much of the work themselve.

The house, with 3000 square feet of floor space on three floors, cost $65,000. In 1973, after two years away teaching and studying at Harvard, the Simmonses celebrated their return by building the swimming pool.

Last year, with contractor Joe Namuth, the Simmonses built the south section, 2000 square feet for $95,000, a reflection of the steep inflation of the past ten years. An other note of the times: the old section cost $65 to heat with gas in January. The new, $300 to heat with electricity.

If their money holds out, next year the Simmonses would like to build a greenhouse on the back to catch the eact sun for Angela Simmons' green thumb.

We think the house is a success," said Simmons. "Because it has served us well for ten years and has accommodated itself to expansion and change. The true test of architecture is history."