THE SWIMMING POOL SEASON. By Rose Tremain. Summit. 274 pp. $16.95.

THE VILLAGE of Pomerac, in France, in which most of Rose Tremain's new novel, The Swimming Pool Season, takes place, is inhabited by an astonishingly varied cast of characters: male and female, aristocratic, middle class and peasant, all of whom we come to know quite well. Each one of them is granted a point of view of equal weight in an unusually fluid and persuasive narrative. There are no breaks or hesitations as events are perceived by one character and then by another, so that the reader is at the center, and it is he who must assign value and make moral judgments.

"The lines of love or longing, if you drew them, they'd crisscross Pomerac like a tangle of wool . . . the old man paid to keep the edges tidy is dreaming of the bosom of Mme. Carcanet . . . From the Mar,echal's foetid room, lines travel not only to Eulalie in her smock but half across France to his dead sons and all the grandchildren who year by year expect news of his death and never come to visit him . . . into the very center of the village, comes the cold, black line of longings of Claude Lemoine. . ." And so on, so that throughout the book at least 20 characters are eventually revealed to us in considerable depth.

The village also has its refugees: an English couple who have exiled themselves to France in an effort to recoup their losses -- both financial and psychological -- after the husband's failure to make a success of his business, which is that of building swimming pools and which serves as a metaphor for much more. "England was pronouncing judgment on his fledgeling enterprise: the swimming pool season is over. Around the corner is winter; moss will bubble up in the splits and cracks of tile. . . A swimming pool is only a pit with plumbing. In time, nature reclaims it as a pond." The plight of this couple provides the central thrust of the plot, although suspense is less important in this novel than the delineation of character. What we are meant to discover is that the characters have arrived where they are because of whatever has gone before in their lives, and sufficient tension is provided by the author's skillful unwinding of the past and her illumination of the present. It is we who are left to imagine the future. When the English wife, Miriam, abandons her husband, perhaps forever, in order to return to Cambridge to care for her dying mother, we are introduced to a whole new set of characters and their tragedies and victories, longings and desires. And it is Tremain's wisdom and empathy that keeps us reading, quite often in spite of ourselves.

ROSE TREMAIN'S career seems to have been moving along at a pretty quick clip because here she is, in her mid-thirties, with her fourth book in print and with a trail of various triumphs in her wake. She is a Fellow of the Royal Society of Literature, was chosen one of the 20 best young British novelists in 1983, and in 1984 won the Dylan Thomas Award for stories included in her first collection, The Colonel's Daughter. Perhaps all this left her too much emboldened, and her courage sped her forth too fast through the writing of this new book. It is mostly a peculiar carelessness that mars this novel in which Tremain's intention is enormous, her passion generous, her voice inventive and even compelling. She is a lyrical and very sensual writer, and her subject is love in all its varieties, but given such a subject, she fails to exercise necessary restraint. Too often she slips into a romantic breathlessness that leaves the reader gasping for air. "He kisses her and both their triumphing faces are wet. And he moves her more than anything in her life. She who is so obedient to beauty, finds in Xavier a lover her enfolding arms want to possess forever. She wants to shout with him. Hurl rocks. Climb the sky."

When Tremain conceives her characters and their situations she is unswerving in her effort to make us see, feel, hear, taste and smell precisely what she has imagined. She is striving for the freshest vision, the exact thing. And this is admirable and sometimes a real strength, but it is too often her greatest weakness. She says about one character, "He's a slim and pale man with thick, cavorting hair." And no less than a male Medusa comes to mind. In the same way, in her seeming obliviousness to the power of the extraordinary sensuality of her own language, she has made use of the present tense and sign-posting -- snatches of songs from Simon and Garfunkel and the Everly Brothers -- so that, now and then, the text seems to be an unnerving combination of Ann Beattie and a bad translation of Colette.

Nevertheless, this is an oddly seductive book. Tremain is extremely intelligent and she has a marvelous wit, a generous -- not cynical -- humor. It might be that no amount of caution could have pulled this endeavor together successfully, because Tremain means to have the reader understand and define for himself the condition of the human heart, the entire terrain of love and loss. I admire her ambition in taking on so large a task, and I'm very glad she's crossed the Atlantic, because her true voice, when she employs both her discipline and discretion, is rich, and lush, and elegant.