Is Your Is Your Well Water Safe?Well Water Safe?
byby
Bob SchultheisBob SchultheisAgricultural Engineering SpecialistAgricultural Engineering Specialist
MissouriMissouriWater Supply StatisticsWater Supply Statistics
890,000 Missourians on private water supplies
86% on drilled wells 300,000-350,000 active wells 10,000-20,000 new wells drilled annually One abandoned well or cistern for every
80 acres of land (DNR estimate)
– Webster Co. = 4,700+ wells over 379,000 ac.
What is Coliform?What is Coliform?
Coliform bacteria are used as indicator organisms to test for contamination of drinking water.– >1 coliform = “Unsatisfactory” in DOH tests
E. coli is a member of the coliform family and is commonly found in raw sewage.
E. coli is responsible for manyhealth-threatening diseases.
Coliform-Associated Coliform-Associated DiseasesDiseases
Cholera Typhoid Salmonella Shigella Staphylococcus Hepatitis A, B, C Polio Viral Gastroenteritis
1994 Coliform Detection 1994 Coliform Detection StudyStudy
May to Nov. 1994 well survey 9 states- Illinois, Iowa, Kansas,
Minnesota, Missouri, Nebraska,North Dakota, South Dakota, Wisconsin
41.3% tested positive E. coli detects averaged 11.1% Missouri E. coli detects - highest at
22.6%
Sampling Sampling ResultsResults
Private WellsPrivate Wells
Area 1 Area 2 Area 3 Area 4 Area 5 Area 6 Sp Area
0
20
40
60
80
100
TC EC NO3-N
1
2
3 4
5
6
Factors Contributing to Factors Contributing to Coliform DetectsColiform Detects
Improperly constructed wells Poorly maintained wells Ineffective on-site sewage systems Proximity to livestock feeding
operations Karst geologic formations
NitratesNitrates
Nitrate detects are relatively low although not uncommon. (up to 16% of samples)– >10 ppm NO3-N = “Unsatisfactory”
Sources– Livestock facilities (esp. abandoned ones)– N & P fertilizer in excess of crop removal
capability– Failing septic systems
D.O.H. Water Quality D.O.H. Water Quality SurveySurvey
August 1999August 1999
Webster County“gridded” for random sampling
61 participants
D.O.H. Water Quality D.O.H. Water Quality SurveySurvey
August 1999 Results - Webster August 1999 Results - Webster CountyCounty
44%
Private wellstesting positive
for coliform bacteria
28%
Sewage systemswith open discharge& surfacing effluent
Soils in Webster CountySoils in Webster County 79% rated “severe” for pollution 79% rated “severe” for pollution
potentialpotential 21% rated “moderate”21% rated “moderate” 0% rated “slight”0% rated “slight”
“Losing” stream
Solution Channel
What’s Wrong with this What’s Wrong with this Well?Well?
Ways to ReduceWays to Reduce Well Contamination Well Contamination 11
Soil blanket (5+ feet thick) is good filter
Elevation = keep above pollution sources
Distance = 200+ feet horiz. separation
Grout well with neat-cement or bentonite clay by state-certified well driller
Use approved sanitary well cap
Rehab. poorly constructed wells
Ways to ReduceWays to ReduceWell Contamination Well Contamination 22
Plug abandoned wells & cisterns
Repair/move/replace failing septic systems
Apply fertilizer & animal manure according to soil test & manure test
Repair/upgrade animal waste facilities
Install containment for fuels & pesticides
Ways to ReduceWays to ReduceWell Contamination Well Contamination 33
Don’t dump anything into sinkholes
Use grass buffer strips (50+ feet wide)as filters around sinkholes
Promote community awareness of risk
Shock-chlorinate active wells after anyplumbing repairs
Shock-Chlorinating YourShock-Chlorinating Your6-inch Diameter Well 6-inch Diameter Well 11
Remove well cap or unscrew vent pipe
Newer wells Older wells
Shock-Chlorinating YourShock-Chlorinating Your6-inch Diameter Well 6-inch Diameter Well 22
Mix chlorine & water inbucket. Pour into well– Liquid bleach @ 1 pint
per 25’ of water depth, or– Chlorine tablets @ 0.5 lb.
per 150’ of water depth Circulate water back down well Load chlorinated water into
plumbing system
Shock-Chlorinating YourShock-Chlorinating Your6-inch Diameter Well 6-inch Diameter Well 33
Let chlorine water stand insystem at least 12 hours
Flush system with water,starting outside
Retest for bacteria after 7-10 days– $10 cost; DOH has sterile sample bottle – Keep sample cool & dark, get to lab in 6 hours
Keep test results with important papers
University InformationUniversity InformationGuides AvailableGuides Available
WQ100 Water Testing: What to Test For WQ101 Understanding Your Water Test
Report WQ102 Bacteria in Drinking Water WQ103 Nitrate in Drinking Water WQ104 Understanding Home Water
Treatment Systems
Questions??Questions????
Robert A. (Bob) Schultheis
Agricultural Engineering Specialist
Webster County Extension Center
800 S. Marshall, P.O. Box 7
Marshfield, MO 65706-0007
Voice: 417-859-2044
Fax: 417-468-2086
E-mail: [email protected]
Website: http://outreach.missouri.edu/webster
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