Tens of thousands of Texans living along the Rio Grande are still using pit toilets and some must travel up to 30 miles for a jug of fresh water, according to a congressional study.

A General Accounting Office study of six border counties in Texas found 198,000 people are living in 842 colonias -- unincorporated, rural subdivisions with frequently substandard housing, inadequate roads, a lack of running water or adequate sewage systems.

Sixty percent of the colonias surveyed have water supplies but less than 1 percent -- a total of three -- have public sewage disposal systems, according to the GAO report released Wednesday.

"I'm very concerned that the lack of proper waste systems for these colonias poses a growing health risk to residents and their children. It's also contributing to environmental problems along the border," said Rep. E "Kika" de la Garza (D-Tex.).

De la Garza, chairman of the House Agriculture Committee, said the study "substantiates the need to continue and strengthen our efforts to bring adequate water and sewer facilities to the hundreds of thousands of colonia residents along the Texas-Mexico border." The six counties surveyed -- El Paso, Webb, Starr, Hidalgo, Willacy and Cameron -- have 91 percent of Texas colonias residents, the report said. An earlier study by the Congressional Research Service found 10,850 people were living in 61 colonias in the state's other 10 border counties in 1987.

The GAO also found 14,600 people were living in 15 colonias in New Mexico's Dona Ana County. Twelve colonias had access to public water and only one had access to a public sewer.

Although a colonia may have a water system, residents do not necessarily have running water, the GAO said.

"In some Texas colonias, residents have only outside water spigots to provide water and do not have indoor plumbing. Sometimes residents have not hooked up to the water system because they cannot afford the user fees," the study said. And local officials believe most of the on-site sewage systems used in colonias are substandard, the GAO study also reported.

"Some residents travel as far as 25 to 30 miles to any of three county-owned water spigots to fill their water containers," GAO said. "Pit privies are the primary method of sewage disposal for Webb County colonias."

Texas voters last year authorized $100 million to fund water and sewer projects in counties with economically distressed areas and in all border counties with colonias.