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Protecting Your Wellhead from Contamination

The area around your wellhead is the easiest place to prevent contamination. Here are the habits that keep it safe.

By Know Your Well Water Editorial TeamReviewed October 29, 20262 min read

Quick Answer

Keep contaminants away from the wellhead, maintain an intact cap and casing that extends about 12 inches above grade, and make sure the ground slopes away so water drains off. Store chemicals, fuel, and waste well away from the well, and test your water at least once a year.

The wellhead is your front line

Most preventable well contamination starts at the surface, right around the wellhead. A sound cap, a casing that stands above grade, and ground that drains away form a simple barrier against the spills, runoff, and debris that would otherwise find their way into your water.

  • Keep the casing about 12 inches above grade and the cap sealed and vented.
  • Slope the ground away from the wellhead so water drains off.
  • Store fuel, pesticides, fertilizer, and chemicals far from the well.
  • Keep livestock, manure, and pet waste away from the wellhead.
  • Maintain safe separation from septic systems and tanks.

Watch what happens nearby

Spills, flooding, and construction near the well can introduce contaminants quickly. After any such event, treat the water as potentially unsafe until it has been tested, and never judge safety by how the water looks.

A printable wellhead checklist

  1. 1Cap intact, tightly sealed, and vent screen in place.
  2. 2Casing above grade with no cracks or corrosion.
  3. 3Ground slopes away; no pooling at the wellhead.
  4. 4No chemicals, fuel, or waste stored nearby.
  5. 5Recorded this year’s bacteria and nitrate test results.

Mowing, landscaping, and runoff can change conditions around the well over time, so recheck the grade and the casing seal each year. A few minutes of attention at the wellhead is the cheapest contamination prevention you can do.

Frequently asked questions

How far should chemicals be stored from a well?
Keep fuel, pesticides, fertilizer, and other chemicals as far from the wellhead as practical and follow local setback requirements. The further away, the lower the contamination risk.

Sources & references

This guide is documentary research and general information, not a laboratory analysis or professional assessment of your specific well. See our disclaimer.