Well Water Safety

Contamination of Well Water

Pathways of Contamination

In aquifers, contaminants and recharge waters can follow similar pathways and can contaminate the groundwater in the following ways:

Bacteriological Contaminants

Total Coliforms

What are Total coliforms?

E. Coli

What is E. coli?

Chemical Contaminants

Nitrates and Nitrites

Other Chemicals

Gas and Well

Fuels (Gasoline, Diesel, Heating Oil)

Any chemical or fuel spills that infiltrate the ground can contaminate your drinking water source. It only takes one litre of gasoline to contaminate 1 million litres of groundwater. Check that gasoline, pesticides, and other chemicals are stored in proper containers designed to help prevent spills or leakage. Don’t store these materials anywhere near your wells.

Remember the following


Contaminant sources affecting your well are most often found in your own backyard. Eliminate gardens adjacent to your well. Plant a permanent low-growing ground cover such as grass. Don’t use fertilizers or pesticides.

You should test for these if you are concerned about past or present use of pesticides near your well, if you’ve had a spill or leak, or if you are concerned about possible backflow through your plumbing into your well during mixing of pesticides.