When Should You Test Your Well Water? A Summer Checklist

Most well water homeowners know they’re supposed to test their water annually, but fewer than half actually do it. And of those who do, many test at the wrong time of year and miss the conditions that matter most.

Summer is the single best time to test your private well. Here’s why, what to test for, and what to do with the results.

Why Summer Is the Best Time to Test

Well water quality isn’t static. It changes with the seasons, and summer tends to bring out the worst in it. Three things happen between June and September that make summer testing so valuable:

Spring Runoff Has Had Time to Reach Your Aquifer

Snowmelt and spring rain carry surface contaminants such as agricultural chemicals, road runoff, and septic influence downward through soil and into groundwater. This process takes weeks to months depending on your soil type and well depth. By early summer, any contamination that entered during spring has had time to migrate. Testing in spring may actually miss it.

Water Tables Are at Their Seasonal Low

Lower water levels in summer mean dissolved minerals, iron, manganese, and naturally occurring gases are more concentrated. If your water has borderline iron or hardness levels, summer is when those numbers will be at their highest. Testing now gives you your water at its most concentrated and the conditions your treatment system has to handle at peak demand.

Bacterial Activity Increases With Warmer Temperatures

Iron bacteria, sulfur bacteria, and coliform bacteria all become more active as groundwater temperatures rise. If your well has any biological contamination, summer is when it’s most likely to show up in a test and when the effects on your water quality and treatment equipment are most pronounced.

According to the CDC and EPA, private well owners should test at minimum once per year and after any event that could affect water quality.

Your Summer Well Water Testing Checklist

✅ Test for These Every Year

• • Coliform bacteria — the most important annual test. Coliform indicates potential contamination from surface water, septic systems, or animal waste. E. coli specifically signals fecal contamination and requires immediate action.
  • Nitrates — especially important for homes with infants, pregnancy, or older residents. Nitrates come from fertilizer runoff, septic systems, and decaying organic matter. The EPA limit is 10 mg/L.
  • pH — low pH (acidic water) corrodes pipes and leaches lead and copper. High pH affects taste and can interfere with disinfection. Target range for most treatment systems is 6.5–8.5.
  • Hardness — tells you how much calcium and magnesium is in your water. Relevant for softener sizing and performance verification.
  • Iron and manganese — the most common well water aesthetic problems. Iron above 0.3 mg/L causes staining; manganese above 0.05 mg/L causes black staining and has health implications at higher levels.
  • TDS (Total Dissolved Solids) — a quick snapshot of overall mineral load in your water.

✅ Test for These Based on Your Situation

• • Arsenic — naturally occurring in many regions, particularly the Southwest, New England, and parts of the Midwest. No safe level for long-term exposure. Check whether your area has known arsenic in groundwater.
  • PFAS — if you’re near a military base, airport, industrial facility, or known PFAS contamination site. The EPA’s 2024 maximum contaminant level for PFAS is now 4 parts per trillion — far lower than previously regulated.
  • Lead — if your home was built before 1986 or you have older plumbing. Lead doesn’t come from your well — it comes from pipes, solder, and fixtures, but a water test will reveal whether it’s present at your tap.
  • Radon — common in granite geology regions. Radon in water contributes to indoor air radon levels when water is heated or agitated.
  • Hydrogen sulfide / sulfur odor — if you notice a rotten egg smell, especially in summer when bacterial activity increases.

✅ Test Your Treatment System’s Output

If you have an iron filter, softener, or other treatment equipment, summer is an ideal time to verify it’s still performing correctly:

• • Test water after your treatment system, not just before it
  • Iron at the tap should be near zero if your filter is working
  • Hardness at the tap should be near zero if your softener is working
  • pH should be in the 7.0–8.0 range if you have an acid neutralizer

A post-treatment test is one of the most useful diagnostics available, it tells you immediately whether your system is performing as designed, or whether it’s time for a media change, rebed, or equipment check.

When to Test More Frequently

Annual testing is the baseline. Test again if any of the following occur:

• • Flooding near your well or on your property
  • Nearby construction, drilling, or land disturbance
  • A new infant in the household (nitrates)
  • Changes in your water’s taste, odor, or appearance
  • Any work done on your well, pump, or pressure tank
  • A neighbor reports a contamination problem
  • You’ve recently installed or changed treatment equipment

What to Do With Your Results

A water test result is only useful if you act on it. Here’s a simple framework:

If bacteria is detected: Shock chlorinate your well immediately and retest. Do not use the water for drinking or cooking until the test comes back clean. This is a health issue, not an aesthetic one.

If iron or manganese is elevated: Compare pre- and post-treatment results. If your filter is removing it effectively, you’re fine. If breakthrough is occurring, the filter media may need replacement or the system may need to be resized.

If pH is low (below 6.5): Acidic water corrodes pipes and leaches metals. An acid neutralizer or soda ash injection system addresses this directly.

If hardness is high: A properly sized water softener solves scale buildup in appliances, fixtures, and pipes. If you already have a softener, verify it’s regenerating correctly.

If you find something unexpected: Talk to a water treatment specialist before purchasing anything. The right fix depends on your specific water chemistry, flow rate, and household needs — not a generic recommendation.

Start With a Test, Not a System

The most common mistake well water homeowners make is buying a treatment system before they know what’s in their water. A water test takes the guesswork out of the decision entirely and ensures that whatever system you choose is matched to your actual water chemistry.

Summer is the right time. Your water is at its most concentrated, bacterial activity is at its highest, and you have the rest of the season to act on what you find.

Whether you buy from us or not, we hope understanding your well water better helps you give your family the best water possible.

Article last updated July 7, 2026 by Author.