Is Your Well Water Safe?
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Transcript Is Your Well Water Safe?
Is Your
Well Water Safe?
by
Bob Schultheis
Agricultural Engineering Specialist
Missouri
Water 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?
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 many
health-threatening diseases.
Coliform-Associated Diseases
Cholera
Typhoid
Salmonella
Shigella
Staphylococcus
Hepatitis A, B, C
Polio
Viral Gastroenteritis
1994 Coliform Detection Study
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 Results
Private Wells
3
4
2
1
100
5
6
80
60
40
20
0
Area 1 Area 2 Area 3 Area 4 Area 5 Area 6 Sp Area
TC
EC
NO3-N
Factors Contributing to
Coliform Detects
Improperly constructed wells
Poorly maintained wells
Ineffective on-site sewage systems
Proximity to livestock feeding operations
Karst geologic formations
Nitrates
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 Survey
August 1999
Webster County
“gridded” for
random sampling
61 participants
D.O.H. Water Quality Survey
August 1999 Results - Webster County
Private wells
testing positive
for coliform bacteria
44%
Sewage systems
with open discharge
& surfacing effluent
28%
Soils in Webster County
79% rated “severe” for pollution potential
21% rated “moderate”
0% rated “slight”
“Losing” stream
Solution
Channel
What’s Wrong with this Well?
Ways to Reduce
Well Contamination
1
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 Reduce
Well Contamination
2
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 Reduce
Well Contamination
3
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 any
plumbing repairs
Shock-Chlorinating Your
6-inch Diameter Well 1
Remove well cap or unscrew vent pipe
Newer wells
Older wells
Shock-Chlorinating Your
6-inch Diameter Well 2
Mix chlorine & water in
bucket. 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 Your
6-inch Diameter Well 3
Let chlorine water stand in
system 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 Information
Guides 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???
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