The house smells of ammonia and lemon. The children are doing homework. An unwatched TV spews animated Spanish and a breeze wafts through the window.

Two undocumented residents and three U.S. citizens -- their children, who were born here -- live in this household in an eastern suburb. Since their arrival from south-central Mexico three years, another three families, also undocumented, from the same pueblo have followed them.

Last week, millions of immigrants marched to protest proposed federal legislation aimed at cracking down on undocumented residents. But for these families in Pittsburgh, legislative proposals lose their immediacy when the utility bill is indecipherable.

"Living is the problem," said the mother of the three children, one of whom huddled up against her at the kitchen table, "just getting a house to live in, and working."

The four families were afraid to speak on the record or say where they worked out of fear they would be discovered and deported. That happens rarely in this area or in most parts of the country, a fact that is driving the legislation in Congress.

Michael Keegan, of the Immigration and Customs Enforcement office in Washington, D.C., said an undocumented resident who does nothing to attract police attention is about as safe "as you and I." If he is stopped for a traffic infraction and has no prior arrests and a valid driver's license, his residency status would not be relevant.

All but two of the eight adults in the four families work multiple jobs, mostly in housekeeping and landscaping, and they all share child-care responsibilities.

With no time to take English classes, they struggle to learn the system, from dealing with utility companies to getting a driver's license. During one visit, one of the children ran into the room with a bill which she handed to an English speaker to translate.

"My husband got his driver's license," one of the women said, smiling about this momentous event. "It gives us some freedom." That same day, one of her sisters-in-law was dealing with another rite of passage, paying income taxes.

Although living in scattered locations, the families have created a family cooperative of safety nets. The first arrivals helped the others find jobs with theirs or a related employer. They stagger their shifts and shuttle children to each other's homes, sometimes late at night, to work night jobs. They have saved and bought houses with cash to avoid putting too much information on paper, borrowing and repaying each other as their fortunes shifted.

As fortunes go, theirs are modest, and their strikingly neat, under-appointed homes were inexpensive. But their achievements speak to why so many people risk crossing over and staying.

One of the women described her crossing with her husband, but without their son. "We crossed [the Rio Grande] walking. It was in the day. My son came the same day, but it was safer for him not to come with us. We paid someone to bring him in their car." The others also entered through Texas, but in different places. Some had to swim.

The couple who came first left their children with grandparents for a year. It was a year of longing, overwork and isolation, and, because none are able to speak much English, the isolation continues. It's a bit different for the children. At one of the homes, the first-grader brought home a glowing report card. His language skills had zoomed, and the teacher wrote to the parents, "Keep up the good work!"

On a recent day, the family was preparing for an Easter celebration, and the children were eager. Their parents try not to share their anxieties, but their mother admitted, "I am always worried" about the authorities.

Anxiety is just part of the emotional toll. She hasn't seen her parents for three years and is unlikely to see them soon. "We can't visit our families because coming back is so hard," she said.

A sister-in-law said she hadn't seen her parents for six years. The risks in going back are too high. "We have worked so hard to get this far."

The dilemma is, do they all go back and make it that much riskier , or does one go while the others stay, risking being separated from the children and the home they worked so hard to buy?

Latin Americans make up less than 1 percent of the Pittsburgh area's population, according to the 2000 census, but the number is growing. Sister Janice Vanderneck, who ministers to the Latino Catholic community from a base at St. Hyacinth Church in Oakland, said her workload was mounting "beyond my control."

The Latin-American population of 15,000 in the diocese's five-county area -- Allegheny, Beaver, Butler, Washington and Lawrence -- has probably grown since the 2000 census to more than 20,000, she said. She guessed that about a third were undocumented.

"People do say to me, 'You know these people should not be here. They're going against our law and taking peoples' jobs,' " she said. "I always say, 'Please, I'm begging you, tell me what job you wanted that a Latino has. I really want to know. Because employers call me all the time, saying they can't find landscapers and roofers and need nannies and housekeepers."

She said these residents are not drains on the economy but contributors. "Many pay taxes and own homes," she said.

Sister Janice spends much of her time accompanying undocumented workers to the tax office, the Carnegie Library, clinics and hospitals, lawyers' offices, city and county offices, utility offices and banks.

She said adults are often denied help because they do not have legitimate Social Security numbers, but that the city has some "wonderful agencies."

A free clinic is available every Saturday and there's a mobile clinic for children. Other clinics charge based on income, and there is some prenatal care, but for lab fees or surgery "there is no assistance and no charity care programs, unless the person is in danger of death or losing a limb."

Emergency Medical Assistance addresses dire circumstances only, she said, "so most people who have broken arms just have huge bills and don't go for follow-up care."

She told of a man whose heart problems qualified him for emergency assistance, but when he got a bill, he took the bus to see her.

"He hadn't taken the bus often before and got lost. By the time he got to the church, he was crying and scared to death he won't be able to get the health care he needs, or would have huge bills or not be able to work again or die.

"I tell everyone there is no reason to fear the undocumented Latino worker. Most are people with good family values, hard-working, faith-filled, and they will be bilingual and contribute to the diversity of Pittsburgh. I can never accept that these people are criminals."