Water testing results

figure 1: Soils in Webster County:  79% rated "severe" for pollution potential; 21% rated "moderate"; 0% rated "slight"
Figure 1

figure 2: Water facts: All our water comes from precipitation (no underground rivers from other states); Our activities impact five river watersheds (Finley, Gasconade, James, Niangua and Pomme de Terre Rivers); Sinkholes recharge groundwater in only a few days, but do not filter pollutants; Water travels underground up to 15 miles
Figure 2

figure 3: Disease Risks from Failed Sewage Systems: cholera; typhoid, salmonella; shigella; staphytococcus; Hepatitis A, B, C; Polio; viral gastroenteritis
Figure 3

figure 4: Water Quality Survey Grid by Dept. of Health (August 1999): Webster County "gridded" for random sampling; 61 private water wells sampled; Septic systems also checked
Figure 4

figure 5: Water Quality Survey Results (Webster County, August 1999): 44% of private water wells tested positive for coliform bacteria; 28% of sewage systems had open discharge and surfacing effluent
Figure 5

Rural residents of Webster County, Missouri rely on groundwater from drilled wells for drinking water. Results of a 1999 survey show better watershed management is needed.


The majority of the soils in Webster County have moderate to severe limitations for installing conventional septic tank/absorption field on-site waste treatment systems (see Figure 1, right).

Pollution potential is increased near sinkholes and underground faultlines, because rainfall that provides all drinking water can easily move underground with minimal filtering and travel several miles before surfacing or being withdrawn by wells (see Figure 2, right). Raw sewage contains many potentially harmful pathogens (disease-causing organisms) such as E. coli, which is a member of the coliform family (see Figure 3, below right).

Prior to 1999, the Missouri Department of Health data on bacterial contamination of private water wells in Webster County showed a 30 percent contamination rate by coliform bacteria. The Webster County Commission questioned these data and requested a random sampling be done to obtain more reliable figures.

Testing procedure

So in August 1999, the county was divided into horizontal and vertical mapping "grids" (see Figure 4, below right) and a water sample was taken from the private well closest to the intersection of each gridline. These samples were tested for coliform bacteria, which are indicator organisms to test for contamination of drinking water.


Of the 61 private wells tested by the Department of Health, 44 percent showed unacceptable bacterial contamination (see Figure 5, below right). The sites were also surveyed visually for sewage runoff. Open discharge of sewage was found on 28 percent of the sites.

For more information

MU Extension publication EMW1026, Safe Drinking Water in an Emergency

Shock-chlorinating your well or PDF version — Procedure for killing disease-causing bacteria in 6-inch diameter water wells

MU Extension publication EQM103F, Drinking Water Well Management

MU Extension publication WQ101, Understanding Your Water Test Report

MU Extension publication EQ102, Bacteria in Drinking Water

MU Extension publication WQ103, Nitrate in Drinking Water

MU Extension publication EQ401, Septic Tank/Absorption Field Systems: A Homeowner's Guide to Installation and Maintenance

MU Extension publication WQ402, Residential Sewage Lagoon Systems: A Homeowner's Guide to Installation and Maintenance