Gov. Jay Nixon has yet to sign the bill, and the residents also have to vote to approve it.
However, Missouri lawmakers have approved the idea of Holts Summit and Lake MyKee becoming one city.
The Senate voted 31-0 Friday to send the House-passed bill to Nixon. The House approved the measure March 31 by a 149-1 margin.
"I'm thrilled this has gone through without any amendments and will go to the governor," House sponsor Travis Fitzwater, R-Holts Summit, told reporters after Friday's mid-morning Senate vote.
Sen. Jeanie Riddle, R-Mokane, handled Fitzwater's bill in the Senate.
"The need for this consolidation began with the need for Lake MyKee to update their sewage treatment system," she told the Senate on Friday. "This was estimated to cost $1.5 million, divided by approximately 130 (Lake MyKee) households - which was not in the village's financial best interest."
That calculates to more than $11,530 per household.
Riddle said Friday: "By joining the city of Holts Summit, they can spread out the costs of this update and do so at a lower cost by connecting into that city's sewer system."
Holts Summit already has an agreement with Jefferson City for sewage treatment.
Jefferson City Counselor Drew Hilpert told the News Tribune last month that the agreement with Jefferson City requires Holts Summit to pay "a flat fee for the total amount of sewer used by its residents" at the Jefferson City treatment plant. "They are allowed a certain amount of flow before the charge increases."
The proposed Holts Summit/Lake MyKee merger should have little if any effect on that agreement.
Hilpert said, "So long as the flow did not go beyond the allowable flow, there would be no impact. If it did (go higher), they would be paying more."
State law already allows communities within a half-mile of each other to merge - but the two Callaway County towns are eight-tenths of a mile apart, at their closest point.
The proposed new law extends the allowed separation to a mile and targets communities in first- and second-class counties to join "that have entered into one or more intergovernmental agreements related to municipal services and are connected by at least two publicly maintained rights of way."
They can agree to merge in any of the classifications the state has for small communities - Holts Summit is a city, but Lake MyKee is a village.
Riddle and Fitzwater both said the bill, if signed into law by Nixon, allows the two communities to conclude the merger talks they already have been having, including details about tax rates, the kind of government that will control the communities if voters approve the merger and where the new boundaries will be.
"These two towns began working together on the sewer treatment last year and would like to expand on that service and receive additional services, such as policing, by consolidating as one government," Riddle told colleagues Friday. "The idea to consolidate is strongly supported by the residents of Lake MyKee, as over 90 percent of the citizens have signed documents agreeing to it."
The House also added three Iron County towns to Fitzwater's bill - an addition that pleased Sen. Gary Romine, R-Farmington, whose southeast Missouri district includes Ironton, Arcadia and Pilot Knob.
"These three communities, over the years, have grown to where they're (almost) touching each other," he said, "and this will allow them to take to a vote of the people to do a consolidation."
Fitzwater said adding the Iron County towns to his bill was no big deal.
"They had a similar situation, where they are required to do some infrastructure spending in those small communities," Fitzwater told reporters. "It costs millions of dollars to do sewage treatment plants (with) some of these new requirements and regulations."
State Sen. Mike Kehoe, R-Jefferson City, said after Friday's vote: "This is probably the most affordable solution for that area."
Still, he said, the federal government is causing many of the issues.
"That's one of the things - the more that we have regulations coming in from the EPA, that then the DNR is promulgating - that restrict all these water rights issues and wastewater issues and clean water issues," Kehoe said, "the more that we have an overreaching government that says, 'I'm going to - I don't care what your neighborhood or your system or your sewer or your fresh water is like, we want you to impose these clean water standards' or whatever it is. I think the fight begins at pushing back at that, so we can do common-sense, reasonable things in some of our small communities around the state."
Riddle said the merger has other benefits, including law enforcement.
"Right now, it's about 20 minutes for a (response to a) 911 call to reach (Lake MyKee), as opposed to 3-5 minutes (from Holts Summit)," she explained. "That's pretty good, if you're on the other end of that 911 call."
Because there's only one week to go in the Legislature's session, the bill likely won't be sent to Nixon until after the end of next week, and the governor will have until mid-July to sign it.
Local officials must certify ballot issues to the county clerk by May 24 to be on the Aug. 2 primary election ballot, so a Nov. 8 election seems more likely to be the earliest chance Holts Summit and Lake MyKee voters can approve or reject the proposed merger.
"They're on a timeline," Riddle told reporters. "They were hoping this would pass a year ago."