2. Water Quality and Testing
Drinking water standards
Common contaminants
Testing
Why?
When?
What?
3. Drinking Water Quality
Federal Safe Drinking Water Act, 1974 (SDWA):
Establishes standards for surface and groundwater
sources used for drinking water.
EPA sets standards based on whether a
contaminant:
1. Harms human health
2. Is known to occur in drinking water
3. Can be detected in drinking water
TCEQ is required to enforce the SDWA
Water Quality Law and Policy
4. Texas Private Well Regulations
• Well location requirements
• Well construction
• No requirements for water
testing or maintenance
after construction
Water Supply Regulations
EPA – National Drinking
Water Standards
• Public water systems
• Primary Standards – Health
• Secondary Standards –
Nuisance
• Can be used as a guide for
your private well.
5. Secondary Standards
• Secondary standards, or SMCL
• Set for aesthetic considerations
Taste
Color
Odor
• 15 contaminants
• Examples:
Iron
Sulfate
TDS
EPA Drinking Water Standards
Primary Standards
• Maximum Contaminant
Level, or MCL
• Pose risks to human health
• Over 80 contaminants
• Examples:
Nitrate
E. coli
Arsenic
Organic chemicals and
pesticides
6. Summary of Screening Results
Number of samples screened: 11
Positives coliform: 5 (45%) Positives E. coli: 0
Nitrate average (ppm): 0.5 Range: 0 - 2
Salinity average (ppm TDS): 578 Range: 380 - 901
pH average: 8.1 Range: 7.8 – 8.4
7. Water Well Testing FAQs
How often should the well be tested?
• Annually for bacteria
• Every few years for general chemistry such as
nitrates and salts
• As frequently as needed for other contaminants of
concern
How much will it cost?
• Varies depending on analyses selected.
• Basic E. coli test should be less than $30
8. Private Well Testing
Drinking Water Testing:
• County Health Departments and River Authorities
• NELAC-certified labs on TCEQ website
http://www.tceq.texas.gov/goto/certified_labs
512-239-3754
10. Private Well Testing
Irrigation and Livestock:
Texas AgriLife Extension Service Soil, Water and Forage
Testing Laboratory at TAMU (http://soiltesting.tamu.edu/)
13. Fecal Bacteria
Microscopic organisms
found in feces of humans
and other warm-blooded
animals
Not all are harmful by
themselves
Indicator organisms:
indicate presence of
pathogenic bacteria,
viruses, parasites
E. coli is the most
commonly tested
14. Why Check for E. coli?
• Indicator bacteria
Indicates disease risk from
other organisms that are
pathogenic
• Cost effective
• MCL (maximum contaminant
level) is 0 colonies/100 ml
• Test annually and each time
the well is opened or repaired
22. ANIMAL WASTE
Sources of Nitrates
• 150 FT. SEPARATION FOR PETS AND LIVESTOCK
• WILDLIFE: NO GUIDELINES
23. • Level of dissolved minerals,
including salts
• More than 500 ppm tastes
salty
• Sodium is often referred to as
a measure of salinity, most
common cause of high TDS in
Texas
Total Dissolved Solids (TDS)
24. .
Salinity Tolerance - Plants
PPM
0 - 175 Excellent, no risk to plants
175 – 525 Good, not for sensitive plants
525 – 1,400 Permissible, not for low salt
tolerant plants
1,400 – 2,100 Doubtful, damage to high salt
tolerant plants
>2,100 Unsuitable
26. .
Salinity Tolerance - Animals
PPM
0 - 3,000 O.K. for all livestock
3,000 – 4,999 Satisfactory, may result in temporary
refusal/diarrhea; poor quality for poultry
4,999 - 6,999 Reasonably safe, not for pregnant/
lactating animals
6,999 - 10,000 Risky to young, pregnant/lactating animals
or animals under heat stress
>10,000 Unsuitable for all livestock
27. Iron and Manganese
• Nuisance –unpleasant taste,
odor, and color
• Secondary MCL:
Iron = 0.3 ppm
Manganese = .05 ppm
• Stains- Iron (reddish brown)
Manganese (brownish black)
on concrete, laundry, and
plumbing fixtures
28. Iron and Manganese Treatment
Treatment depends on type and
concentration
• Initially clear, but particles form
and settle out
• Water from tap has solid
particles or has a tint
• Iron/manganese bacteria-
reddish or black slime in toilet
or faucets.
Treatment: Phosphate injection, water softener, oxidizing filter, aeration/filtration,
shock treatment and filtration
29. Hydrogen Sulfide
• Colorless gas with a “rotten egg” odor
• Formed by sulfur- and sulfate-reducing bacteria that can occur
naturally in groundwater
• Shallow or poorly constructed wells
• Wells drilled in shale, sandstone, near coal or oil fields
30. Hydrogen Sulfide (H2S) Treatment
• If the smell is only from the hot water faucet, problem likely is in
the water heater
Ensure the water heater is set according to manufacturer’s
recommendation – often 140o will help. Careful of scalding.
Problem might be caused by a chemical reaction with the
magnesium control rod (anode)
o Can be removed or replaced with an aluminum or zinc rod.
Consider a tankless heater.
• If the smell is coming from both hot and cold faucets, but only
from water treated by a water softener and not in the untreated
water, problem likely is sulfur bacteria in the water softener.
Hire a water treatment specialist to clean the water softener.
31. Hydrogen Sulfide (H2S) Treatment
• If the smell is strong when the water in both the hot and cold faucets
is first turned on, and becomes weaker or goes away after the water
has run for a while, or if the smell varies over time, the problem is
likely sulfur bacteria in the well or plumbing system.
If from sulfur-reducing bacteria, shock chlorination may treat;
could follow with a UV filter OR manganese greensand filter (up
to 10 ppm) or continuous chlorination system (6 to 75 ppm)
• If the smell is strong when you first turn on the water in both the hot
and cold faucets and is more or less constant and persists with use,
the problem likely is H2S in the groundwater that supplies the well.
A whole house carbon filter may remove enough (GAC up to 1
ppm and Catalytic C “more” depending on DO).
Aeration tank, early-style pressure tank bladder (up to 2 ppm)
33. What to Test for: Nearby Land Use
Problem Type Symptoms Recommended Test
Leaking fuel tank Hydrocarbon scan, VOCs
Landfills TDS, pH, heavy metals
Gas or oil drilling
TDS, chloride, sodium, barium, lead,
pH, corrosivity, strontium
Coal mining
TDS, iron, sulfate, pH, corrosivity,
manganese, aluminum
Septic system failure Fecal coliform/E. coli , nitrate
Intensive agricultural use
Total coliform, nitrate, pesticide
scan, pH, TDS
If suspect or observe
34. What to Test for: Nuisance Problems
Problem Type Symptoms Recommended Test
Red or brown Iron
Black Manganese
Reddish-brown slime Iron bacteria
White deposits, soap scum Hardness
Rotten egg Hydrogen sulfide
Metallic pH, iron, zinc, copper, lead
Salty TDS, chloride, sodium
Septic, musty, earthy Coliform bacteria, iron, methane
Gasoline or oil Hydrocarbon scan, VOCs
Soapy Surfactants, detergents
Brown, yellow, reddish Iron
Cloudy Turbidity, suspended solids
Black Manganese
Stains on Fixtures or
Plumbing
Odor or Taste
Appearance of water
35. What to test for: Health Concerns
Problem Type Symptoms Recommended Test
Gastrointestinal illness
coliform bacteria,
sulfates, Giardia
Water supplies used for infants less
than six months old, pregnant or
nursing women, or elderly with
genetically impaired enzyme system
Nitrates
Family member on recommended
low-sodium diet Sodium
Dicoloration of children's teeth Fluoride
Uses or
Symptoms
39. Water Treatment Options
• Particle and microfiltration
• Activated carbon filter
• Reverse osmosis
• Distillation
• Ion exchange – water
softening
• Disinfection
• Continuous chlorination
• Ultraviolet light
40. Water Treatment
• Test your well
• Locate contamination source if
possible
• Check well construction
• Inspect septic system
• Eliminate source of
contamination
• Consider drilling new well
Point of Entry (POE)
Treats water as it enters a
home, whole house
Point of use (POU)
Installed at the faucet
46. • Fecal coliform/E. coli bacteria
Indicator bacteria
Indicates risk from other disease-causing organisms
E. coli from human and animal digestive systems
• Iron, manganese, and sulfur-reducing bacteria
Nuisance bacteria, not a health risk
Bacteria
47. Shock Chlorination
• Method of disinfecting a water well
• Not a long term solution – does not address source
• Should be done anytime well system is “opened”
• Recommended to contact a licensed well driller
• If homeowner does it, make sure to follow correct procedure
Treating Bacteria
48. Shock Chlorination of Stored Water
• Check to see if storage tank is the source
• Determine the correct amount of chlorine
Treating Bacteria
50. Ultraviolet systems (UV)
• Disrupts bacteria life cycle
• More effective than chlorine
• Low cost to operate
• Easy to maintain
• No taste or odor
Treating Bacteria
51. • Filtration
Several types of filters
Remove suspended solids
Filters are made to remove specific particles sizes
Can be used prior to other water treatments
Filtration
52. Filtration
Media Filters
Used for suspended solids
Often used prior to other water treatment devices
Requires back
flushing
Point-of-Entry
53. Cartridges
Primarily used
for suspended
solids
Sized by pore
space and flow
rate
Filtration
Replace filters to avoid clogging
Size by targeted contaminant
54. Activated Carbon Filters
• Coal or charcoal surface absorbs contaminants
• Processed to make large surface area available for adsorption
or chemical reaction
• Replace carbon regularly
• Point-of-use
• Most common
May treat:
― Chlorine
― Color
― Lead
― Radon
― Taste and odor
55. Reverse Osmosis (RO)
• Effective for a variety of
contaminants
• Pressure forces water
through a membrane
• Point-of-use
• Could overwhelm septic
Problem
Pollutants
Aluminum, Arsenic, Asbestos, Barium, Cadmium, Chloride,
Chlorine, Chromium, Copper, Fluoride, Iron, Hardness, Lead,
Magnesium, Manganese, Mercury, Nitrate, Radium, Radon,
Silver, Sodium, Sulfate, Endrin, Heptachlor, Lindane
56. Ion Exchange – Water Softener
Water softeners
• Calcium and magnesium ions exchanged with
sodium or potassium
• Can remove some dissolved metals
• Will not remove particles, pathogens, organic
chemicals
• Works best if water has been pre-filtered
57.
58.
59.
60. Resources on specific water quality issues available
through: twon.tamu.edu and agrilifebookstore.org
