Private well water test interpreter
Understand your well water lab report before you panic.
Enter common private well test results and learn what they mean in plain English. Built for homeowners with private wells, rural properties, and home-buying inspections.
Common urgent flags
- E. coli / total coliform
- Nitrate > 10 mg/L as nitrogen
- Arsenic > 10 ppb
- Lead in first-draw sample
Contaminants
Nitrate
High nitrate can be dangerous for infants and pregnant people.
10 mg/L as nitrogenArsenic
Long-term arsenic exposure is linked to cancer and other chronic health risks.
10 ppb EPA MCLLead
Lead is especially harmful for children and pregnancy, even at low levels.
15 ppb EPA action level; no safe level for childrenTotal Coliform
Coliform bacteria indicate a possible pathway for contamination into the well.
AbsentE. coli
E. coli suggests fecal contamination and can cause acute illness.
AbsentpH
Low pH can corrode plumbing; high pH can cause scale and taste issues.
6.5 to 8.5 secondary rangeHardness
Hard water causes scale, appliance wear, and soap inefficiency.
No health MCL; >120 mg/L is hardIron
Iron stains fixtures and laundry and can create metallic taste.
0.3 mg/L secondary standardManganese
Manganese can cause black staining and may have health concerns at elevated levels.
0.05 mg/L secondary standardTotal Dissolved Solids
High TDS can indicate salty, mineralized, or otherwise poor-tasting water.
500 mg/L secondary standardFluoride
Too much fluoride can affect teeth and bones over time.
4.0 mg/L EPA MCL; 2.0 mg/L secondary standardSodium
Sodium matters for people on sodium-restricted diets and may indicate saltwater intrusion.
20 mg/L advisory for low-sodium dietsFind answers by water problem
Rotten Egg Smell in Well Water
Water smells like rotten eggs, sulfur, or sewage.
Orange or Rust Stains from Well Water
Sinks, tubs, toilets, or laundry develop orange-brown stains.
Black Stains in Well Water
Black staining appears on fixtures, laundry, or toilet tanks.
Blue-Green Stains from Well Water
Blue or green stains appear around drains and fixtures.
Salty Tasting Well Water
Water tastes salty, brackish, or mineral-heavy.
Metallic Taste in Well Water
Water tastes metallic, bitter, or like pennies.
Cloudy or Milky Well Water
Water looks cloudy, white, or milky in a glass.
Brown Well Water
Water turns brown, tea-colored, or muddy.
Slime in Toilet Tank from Well Water
Orange, black, or clear slime grows in toilet tanks or filters.
Popular well water result questions
What Does Coliform Present Mean in Well Water?
A coliform present result means bacteria were detected and your well may have a contamination pathway. Learn what to do before drinking the water.
UrgentNitrate 12 mg/L in Well Water: Is It Safe for Baby Formula?
Nitrate at 12 mg/L as nitrogen is above the EPA limit for drinking water. Learn why baby formula should not be mixed with this water.
UrgentArsenic 15 ppb in a Private Well: What Should You Do?
Arsenic at 15 ppb is above the 10 ppb EPA drinking water limit. Learn immediate steps, retesting, and treatment options for private wells.
SoonPFAS 4 ppt in Well Water: Which Filter Should You Use?
PFAS around 4 ppt can trigger concern under modern drinking water guidance. Compare carbon, reverse osmosis, and ion exchange filters for private wells.
SoonWell Water Test Results Interpretation: What Your Lab Report Means
Learn how to read private well water test results, identify urgent health flags, compare units, and decide what to test or treat next.
RoutineShould You Shock Chlorinate a Well After Coliform Positive?
Shock chlorination is often used after a coliform positive test, but the well should also be inspected and retested before drinking the water.
UrgentPrivate Well Testing After a Flood: What to Test Before Drinking
Floodwater can carry bacteria, fuel, sewage, pesticides, and sediment into private wells. Learn what to test and when to use bottled water.
UrgentTotal Coliform Positive Well Water: Is It Safe to Shower?
A total coliform positive result usually means do not drink untreated well water. Learn when showering may be acceptable and when to be more cautious.
UrgentE. coli Present in Well Water: What to Do Immediately
E. coli in private well water suggests fecal contamination risk. Learn immediate water-use precautions, inspection steps, and retesting.
UrgentNitrate 10 mg/L in Well Water: Is It Safe?
Nitrate at 10 mg/L as nitrogen is right at the drinking water limit. Learn what it means for infants, pregnancy, and retesting.
SoonNitrate 20 mg/L in Well Water: What Should You Do?
Nitrate at 20 mg/L as nitrogen is above the drinking water limit. Learn immediate steps and treatment options for private wells.
UrgentArsenic 10 ppb in Well Water: Is It Safe?
Arsenic at 10 ppb is at the federal drinking water limit. Learn why many homeowners still consider treatment and follow-up testing.
SoonLead 5 ppb in Well Water: Is It Safe for a Child?
Lead can be harmful for children even at low levels. Learn what a 5 ppb well water result means and what to do next.
UrgentWell Water Smells Like Rotten Eggs: Is It Safe to Drink?
Rotten egg odor often points to hydrogen sulfide or bacteria. Learn when odor is a nuisance and when testing is needed before drinking.
SoonOrange Stains in Well Water: Iron or Iron Bacteria?
Orange stains can come from dissolved iron, iron bacteria, or corrosion. Learn what to test before choosing a filter.
RoutineBlack Stains in Well Water: Manganese and Infant Safety
Black staining can be a clue for manganese. Learn why manganese matters for infant formula and what to test next.
SoonHard Water 180 mg/L in Well Water: Do You Need a Softener?
Hardness around 180 mg/L as CaCO3 is considered hard water. Learn when a softener helps and what it will not fix.
RoutineLow pH 6.0 Well Water and Copper Pipes: What It Means
Low pH well water can corrode plumbing and release copper or lead. Learn what to test and how neutralizers work.
SoonTDS 500 mg/L in Well Water: Is It Safe?
TDS around 500 mg/L can affect taste and may signal minerals, salts, or treatment issues. Learn what to test next.
RoutineSodium 100 mg/L in Well Water and Low-Sodium Diets
Sodium in private well water can matter for people on sodium-restricted diets. Learn what a 100 mg/L result means.
SoonUranium in Well Water: Treatment Options for Private Wells
Uranium can occur naturally in private wells. Compare reverse osmosis, anion exchange, and testing steps.
SoonRadon in Well Water: Aeration or Carbon Filter?
Radon in well water can enter indoor air. Compare aeration and granular activated carbon treatment approaches.
SoonWell Water Test Before Buying a House: What to Include
Buying a home with a private well? Learn which water tests to request before closing and why bacteria-only testing is not enough.
SoonAnnual Private Well Water Test Checklist
Private well owners should test at least annually for key contaminants. Use this checklist to plan routine and event-based testing.
RoutineWell Water Test After Heavy Rain: What to Check
Heavy rain can move bacteria, nitrate, sediment, and surface contaminants toward a well. Learn when to test and what results matter.
SoonReverse Osmosis for Well Water: What Does It Remove?
Reverse osmosis can reduce many dissolved contaminants at the tap, but it is not a complete whole-house treatment. Learn what it helps and what it misses.
RoutineUV Light for Well Water Coliform: When It Helps
UV disinfection can inactivate bacteria, but it requires clear water, maintenance, and source correction. Learn when it makes sense.
SoonWater Softener for Well Water Iron: Will It Work?
A softener can handle some dissolved iron, but it is not always the right iron treatment. Learn what to test first.
RoutineChloride 250 mg/L in Well Water and Salty Taste
Chloride around 250 mg/L can cause salty taste and corrosion concerns. Learn common sources and treatment options.
RoutineSulfate 500 mg/L in Well Water: Taste and Diarrhea Concerns
High sulfate can cause bitter taste and laxative effects for some people. Learn what a 500 mg/L result means.
SoonCloudy Well Water After Changing a Filter: What It Means
Cloudy water after a filter change can be air, sediment, carbon fines, or a plumbing disturbance. Learn when to test.
RoutineWell Water Test Kit vs Lab Test: Which Should You Use?
Home test kits can screen some parameters, but certified lab testing is better for health decisions. Learn when each makes sense.
RoutineHow to Read Well Water Lab Report Units
mg/L, ppb, present/absent, pH, and grains per gallon can be confusing. Learn how to compare well water results correctly.
RoutinePrivate Well Water and Pregnancy: What to Test
Pregnancy can make nitrate, lead, bacteria, arsenic, and other well water contaminants more important. Learn what to test.
SoonIs Well Water Safe for Infant Formula? Checklist
Before mixing baby formula with private well water, test nitrate, bacteria, and other health contaminants. Use this safety checklist.
UrgentWell Water After a Septic Backup: What to Test
A septic backup or nearby septic failure can affect private well water. Learn which tests to order and when to use bottled water.
UrgentWell Water Near a Farm: What Should You Test?
Wells near farms may face nitrate, bacteria, pesticides, and sediment risks. Learn what to include in a private well test panel.
SoonWell Water Near a Landfill: PFAS and VOC Testing
Private wells near landfills may need testing beyond bacteria and nitrate. Learn when PFAS, VOCs, metals, and other panels matter.
SoonPFAS in Private Well Water: What to Do
PFAS results in private wells can be confusing because limits are low and measured in ppt. Learn confirmation, treatment, and follow-up steps.
SoonMetallic Taste in Well Water: Lead, Copper, or Iron?
Metallic taste can come from iron, copper, low pH corrosion, or plumbing metals. Learn what to test before choosing treatment.
SoonBlue-Green Stains from Well Water: Copper and Low pH
Blue-green stains often indicate copper corrosion from acidic water. Learn what to test and how to prevent plumbing damage.
SoonWhich Filter After a Positive Bacteria Test in Well Water?
A positive bacteria test needs source correction, disinfection, and retesting. Learn when UV, chlorination, or repairs make sense.
UrgentWell Water Test Results: Red Flags to Review First
Not every abnormal well water result has the same urgency. Learn which lab report flags to review first.
SoonUS state well water guides
Alabama
State-specific guide for interpreting results in private wells.
Alaska
State-specific guide for interpreting results in private wells.
Arizona
State-specific guide for interpreting results in private wells.
Arkansas
State-specific guide for interpreting results in private wells.
California
State-specific guide for interpreting results in private wells.
Colorado
State-specific guide for interpreting results in private wells.
Connecticut
State-specific guide for interpreting results in private wells.
Delaware
State-specific guide for interpreting results in private wells.
District of Columbia
State-specific guide for interpreting results in private wells.
Florida
State-specific guide for interpreting results in private wells.
Georgia
State-specific guide for interpreting results in private wells.
Hawaii
State-specific guide for interpreting results in private wells.
Download iOS App
Interpret once on the web. Track forever in the app.
Save test history, set annual reminders, compare results over time, and create a shareable report.
Download the iOS appEducational guidance only. Always confirm important decisions with a certified laboratory, local health department, qualified water treatment professional, or clinician.