Douglas County commissioners are about to open the spigot on expansion of a rural water district southeast of Lawrence.

Commissioners will meet Monday morning to widen the boundaries of Rural Water District No. 4, which covers the rural area east of U.S. Highway 59 between the Wakarusa River and U.S. Highway 56. The district serves 900 customers and about 3,000 residents.

District officials have been pushing for months to secure permission to expand, in hopes of:

• Including the 108 customers who already pay for and receive district water service, but don’t live within the district.
• Accommodating land owners on the district’s waiting list for water service, a list with at least 125 names and growing.
• Making room for even more users, as the district’s long-term plan calls for doubling its customer list within 20 years.

Despite such pressures, the district has been prohibited from adding customers for the past three years — because regulations would not allow it and the system’s capacity couldn’t handle it.

County commissioners, meanwhile, have been reluctant to loosen their controls on the district. Back in April, commissioners said they would not consider allowing expansion until the county had wrangled with its own set of regulatory boundaries: Lawrence’s Urban Growth Area.

Last week, commissioners agreed to expand the growth area south of the Wakarusa River. That means developers of new homes built in the area north of what would be North 950 Road no longer will be able to avoid regulations that require granting access for new roads or utilities.

Elimination of the so-called “5-acre exemption” in the growth area means that portions of the water district that are closest to Lawrence now must be developed with an eye toward annexation into the city.

And that satisfies Commissioner Charles Jones, who wanted to be sure that taxpayers would be protected as 20,000 residents are expected to move into the Urban Growth Area within the next 25 years.

“I do worry about sprawl in the unincorporated areas of Douglas County, but this is the best we can do right now,” Jones said. “I’m ready to move.”

The district also has been working on its capacity limitations, having worked out an agreement to buy water from another district in nearby Johnson County. The estimated $1.25 million project would add a new pump station near Eudora and boost the Douglas County district’s existing capacity of 525,000 gallons a day.

Commissioners are scheduled to consider the district’s expansion during their meeting that begins at 9 a.m. Monday at the county courthouse, 1100 Mass.