A high water content produce like watermelon? I wouldn't. Not unless I considered the water in my septic drain field to be potable/drinkable water and I don't think most would.

Dave

If your septic tank and leach field are functioning properly, I doubt there is any contamination of the plant. Outflow from the tank flows downwards in a properly functioning leach field. The water flow from a septic tank is directed such that it flows about 18" below the surface, and moves downwards. Watermelon plants do not grow roots to that depth. As long as your septic system has not overflowed--has been properly maintained, there should be no worry about consuming a plant which has grown on top of the leach field. If the plant was growing right on top of the septic tank, itself, I guess I would be subject to the ick factor.

Lorna

We install septic systems for a living and there's no way I would eat any produce that grew over the drainfield. There are some publications by our state university that indicate it's safe to eat things like tomatoes grown over a properly functioning system but not leafy veggies, partly due to the "splash" factor from watering and rain. However, it would take an examination of a system by a professional to be sure it was functioning properly and that no sewage was contaminating what was grown over it.

The pathogens in sewage, whether anybody in the house has been sick or not, are not meant to be ingested. Watermelons and other veggies are too cheap to take a chance on contracting some illness that could range from a mild upset stomach to hospitalization or death.

(Now you'll hear from all those who have grown their vegetable gardens over their drainfield for years without problem. It's all a gamble!)

Sandy

Research studies have shown that many things besides soil nutrients are transported through the plant root system into the the fruit. Iron, chlorine, calcium, antibiotics, heavy metals, and pathogens including e. coli and salmonella are readily absorbed through the root systems of plants and test out in the fruit produced for as long as 2 years. Perhaps longer but that was the length of the study.

Since this was a volunteer plant to begin with rather than a planned garden planting, and since it is one where a high percentage of the water absorbed by the roots ends up in the fruit itself, is it really worth the risk?

As Sandy said, one would never be advised to intentionally plant a garden on top of a septic field so why would one eat fruit from a volunteer plant that grew there?

Dave

i would let it grow just to see how it does, but then compost it.

Can't speak to the safety of it, but I'm certain the plants will take up liquid from it as evidenced by the fact that I can see where mine are by the obvious darker green of the grass growing above them.

g'day sue,

for me i can't see why not so long as the fruit maybe hasn't been sitting in or on the actual water in the field. there is a whole process that goes on before plants get nutrients and water from such sources (that's why grass & weed growing in these places are so lush and green good nutrient supply) so can't even imagine how any say pathogens would transfer to the flesh of the fruit, even if you thought it was on the skin it could be peeled or washed or both. we also have at least one link to a site that promotes planting over or near leech fields.

and if the septic is working as it should there is a whole process that goes on in the tank before that water is expelled to the leech field. my father used to have a hole dug below the leach field and he would bucket that water to the vege' patch, also had neighbours who micro irrigated their cottage garden with the stuff right from the tank used to stink a bit but no one has suffered.

reckon i would need to see hard case evidence of anyone anywhere actually getting sick from eating produce grown using this water. always an emotive issue with lots of fear hype attached. i hear the same thing about grey water use in gardens we have always used it and to date we rarely even get the common cold.

len

Here is a link that might be useful: len's garden page

Does anyone know the NPK value of urine? It actually has all three in usable form. Its yellow enough to be called liquid gold. Its also rather pathogen free and is normally sterile.
Human waste hot composted is also doable but heavy metals and such tend to be the biggest issue since we are at the top of the food chain. It also depends of what we eat. Vegetarians ? Chicken eaters? Or Tuna and dog? The latter will have very high concentrations since they are top predators while the former will have rather low concentrations of non degradable toxins. Urine however a tragic irony since it really is an ideal fertilizer and we send it where it does the most harm in the oceans and not where it would do the most good in the field.

Being near raw solid waste is a bit of a worry though. Sewage mixing into the water supply is a main cause of 3rd world disease.I would pass on it myself.

See these links for information from VA Tech on this subject.

http://www.ext.vt.edu/pubs/envirohort/426-617/426-617.html

http://www.ext.vt.edu/pubs/farmasyst/442-903/3figure1.html

I agree with other posters above, I would not eat that produce.

On a slightly different topic (but related) I had some small work recently done on my septic system. The contractor, George (a disabled vietnam veteran), had to put his arms in my septic tank to do the work. He proudly exclaimed that he has never gotten sick from doing this.

A few days later, when leaning on his shovel, he told me of another job site, where he was bitten by a copperhead snake. Many construction workers were watching. They were aghast.

During that episode, and right after the snake bite, George promptly showed his wooden leg (claymore mine damage) that the snake had bit. Everybody had a good laugh, except the snake. He was cut in half.

Anyway, I just thought I'd tell the story out of respect for George, who digs septics with less than 1 leg.

gardener_sandy I agree with SOME of what you and digdirt are saying; but, how deep are the leach lines, are you adding bacteria, is anyone in the home sick?
In my cold area we have to bury our lines 20-24 inches minimum. I would eat the melons myself as I don't think enough of the roots will go down far enough (in my area) to get much from the drain field.
Yes gardener_sandy, now you are going to hear about some folks in my area growing gardens over thair leach fields.
We had some folks that don't live in our area come in and demand we put in some kind of septic system, that doesn't work, to reduce the, non-existent, nitrates in our water supply. They say we have Blue Baby Syndrome. We don't, and we have not sense the first settlers in the 1890's. Several folks are growing gardens over their leach fields to test, eat and take to court. I am not one of them as I wouldn't eat carrots, parsnip or horse radish grown over a leach field. Watermelons? Yes.