Is Well Water Safe to Use on a Vegetable Garden? #342803

Asked July 14, 2016, 10:09 AM EDT

Good morning, 
We started a raised-bed vegetable garden this spring, utilizing top soil brought in from a nursery. We have been using our well water to irrigate (hose with a sprayer). We know the well water is contaminated with all sorts of bad stuff (it was tested several years ago by an agronomy lab.)  My elderly in-laws recently suffered a bout of tummy issues after eating their radishes and lettuce. Though they thoroughly washed before eating, they are now assuming that our garden plants have been compromised by the utilization of the well water.  I have eaten several raw (but washed) cherry tomatoes and used a good quantity of herbs (washed, raw and cooked) and not had any issues. My PhD Agronomist father told us this spring that the well water would be safe to use because the e coli and other contaminants would not effect fruit produced by the plants. Though we will now begin using our "city" water for irrigation, I need an impartial source to answer this question (before it turns into a marital problem ;) )  Thanks for any advice you can offer!

Douglas County Nebraska

Expert Response

If the irrigation water is known to be contaminated, then it should not be allowed to touch the edible portions of the garden plants - use drip irrigation rather than a spray. Bacteria can attach to the surface of produce (not just idly sit there) and get in via plant injuries (from hail, insects, rubbing). It takes less than ten bacterial cells to make someone sick and it would be easy to miss a few while washing after harvest, so the best policy is avoidance. Splashing of rainfall off the soil can even transfer bacterial cells to the edible portion of the plant, so if you have access to potable water, that would be the best option.

There has been, and continues to be, a lot of research on this topic (see and for a review and summary of the literature, respectively). Vegetable plants have been shown to take up pathogenic bacteria and viruses in their roots, but the pathogens are not likely to move internally through the plant to the fruit (i.e., tomatoes, raspberries, apples). However, individual studies have shown that lettuce leaves and radish roots can take up E. coli, so use of contaminated water in a garden may pose a risk.

Under the new Food Safety Modernization Act commercial produce growers are required to test their irrigation water several times per year and avoid use of untreated, contaminated water for irrigation because of the risk to consumers (for example, you could reduce the risk by treating your water with chlorine). I know your produce is just for personal use but these regulations are in place for a reason and highlight the need to take the risk seriously.

Small children, the elderly, and immunocompromised individuals are at greater risk of foodborne illness, so if you know your vegetables will be eaten by any of those groups, potable ("city") water would be your best irrigation option.

You say your water is contaminated with "all sorts of bad stuff." Risk associated with heavy metals may also be a concern. Check out the PowerPoint slides at for information about lead, which was shown to be taken up by root crops (carrot), but not leafy (Swiss chard) or fruiting (tomato) crops. The pH of your garden soil may affect the availability of these minerals to your garden crops.

If you have additional questions, feel free to email me directly at <personal data hidden>.
An Ask Extension Expert Replied July 15, 2016, 11:53 AM EDT
Thanks for the info, Connie! I appreciate all of the details.
The Question Asker Replied July 15, 2016, 3:01 PM EDT

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