Sprague Excavating Company in St. Joseph spent Tuesday morning changing out a fire hydrant at 29th and Duncan streets. Missouri American Water is involved in a three- to five-year program that aims to replace aging hydrants and water mains throughout the city.

A recent break in a large Midtown water main points to the uncertainty of patrolling the idiosyncrasies of an aging civic infrastructure.

Missouri American Water crews responded to the area of 22nd and Charles streets June 16 to begin repairs to a broken 18-inch main. Officials say the main is among the oldest in St. Joseph, a group of pipes that badly need replacing to avoid future incidents.

Jody Carlson, the utility’s senior manager for field services and production northwest operations, indicated it’s an impossibility to determine the most problematic pipes in highest need of replacement. But Missouri American still operates on a three- to-five-year plan that strives to replace old pipe wherever it may happen to be located in the city.

“That’s why we’re doing the investment,” Carlson said. “We would like to replace about 1 percent of the water mains each year,” he added. “Roughly, we’ve got 600 miles of main in St. Joseph.”

For 2019, Missouri American intends to spend about $5 million on water main replacements. Carlson said the replacements occur based on such varying factors as location and type of ground. The breaks can happen anywhere.

“We’re not necessarily targeting location, except where we have a higher degree of main breaks,” he said. “There are certain fluctuations in weather that cause damage.”

A weather pattern that features a drying-out period following rains can impact the relative condition of mains. Carlson said settling of the earth can contribute to fissures, and the clay soils common to Northwest Missouri also can result in ground shifts that move the pipes.

It’s typical for St. Joseph to have several water main breaks of different sizes per week. Carlson said a break such as the one on June 16 translates into a “small” revenue loss.

“Nationally, we are probably in the average of main breaks per mile,” he said, adding St. Louis has the highest number of water main breaks per mile in Missouri.

Outdated fire hydrants, some that date as far back as 1919, also come in for attention by the water company. Planning calls for replacing 150 hydrants this year, an increase of 50 over last year’s pace and a match with 2017. The hydrant replacement program is balanced with increasing the flow of fire protection along with growth in St. Joseph that includes new subdivisions. According to Carlson, the goal is to first replace the oldest hydrants in the city up to the 1940s and 1950s.

Flooding has not caused the water service issues in St. Joseph as it has elsewhere. Missouri American’s well field near Amazonia, Missouri, has not been threatened. The location of the utility’s main plant north of St. Joseph on a bluff further ensures protection of the supply. Carlson said the city depends on a system of wells and groundwater instead of the Missouri River.

Filters at the plant have been replaced over the past few years, at costs of $70,000 to $75,000 apiece. A $300,000 capital investment is being made this year into a lime softening program.

Sinkholes have not been a problem for the utility, although the city has recently addressed the issue at several locations on the North End. Keven Schneider, the city’s superintendent of streets and sewers, said the latest sinkholes were discovered in alleys and were being reviewed for potential damage to sewers.

Ray Scherer can be reached

at ray.scherer@newspressnow.com.

Follow him on Twitter: @SJNPScherer.