The problem is consolidating the soil over the drainfield and having deep roots infiltrate the drain system. The drain field "breathes" through the soil and according to our County Health Department no rototilling should be done on its surface. Check with your agency that is in charge of septic systems. People have gardened on top of drain fields for years but that doesn't mean it's not a problem. Tom

Our question/concern is actually more directed to health concerns with eating the vegetables. Is it not true that weeds and wild grasses have deeper roots than vegetable plants? When we prepared the area for a garden, it was an enormous amount of work to extract all of the grass roots.
According to neighbors, there had existed a garden in that spot before. Again, however, our biggest concern is eating vegetables that may have harmful bacteria from the waste water. Does anyone have any previous experience with this?

g'day,

we have a link on our garden page describing how to use a leech/drain field for gardening, i reckon you are going to be waiting a long long time to find any real iron clad information that is likley to show that anyone person has ever been affected by growing above ground vegetables over a leech field, this probably all come back to the 'fear hype' factor?

i would not have suggested that anyone ver till or disturb a leech field but as for creating raised beds over the top of them to me is a good use of a valuable plant food resource, why leave it grass and weeds to draw up all that moisture? just doesn't make sense.

my father used to have a hole dug at the bottom side of our leech filed and he would bail out the water and water the vege's with it.

len

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

How about this:

"Vegetable Gardens and Drainage Fields
Sometimes the ideal place to put a vegetable garden seems to be over the leach field, raising the question of bacterial and viral contamination from the effluent. Soils vary a great deal in their ability to filter viruses and bacteria. Clay soils work best, eliminating bacteria within a few inches of the drain trenches, but sandy soils may allow bacterial movement for several feet. A properly operating system will not contaminate the soil with disease-causing organisms, but it is very difficult to determine if a field is operating just as it should. If at all possible, use your septic drain field for ornamentals and plant your vegetables elsewhere. If you must plant vegetables, take the following precautions. Do not plant root crops over drain lines. Leafy vegetables could be contaminated by rain splashing soil onto the plant, so either mulch them to eliminate splashing or don't grow them. Fruiting crops are probably safe; train any vining ones such as cucumbers or tomatoes onto a support so that the fruit is off the ground. Thoroughly wash any produce from the garden before eating it. Do not construct raised beds over the field; they might inhibit evaporation of moisture."

Here is a link that might be useful: Planting on your septic drain field

Very few Public Health people will recommend planting a vegetable garden over a septic system drain field because that can have adverse affects on the proper draining of the effluent and the potential for disease pathogen growth on the foods.
If at anytime the effluent comes close enough to the surface in that drainfield area there is a problem and that is soil saturation and that means moving the drainfield. Most all of your are young enough to not have any knowledge of the health problems related to sewage in the early 1900's, but if you look in to your history you can see that by far the major limiting factor in life expectency at that time was improper disposal and handling of sewage, and that is still a concern in 3rd world countries. Someone will point out that the chinese farmers have used "night soil", sewage, as a fertilizer for centuries but will fail to alos point out that chinese farmers have many more chronic diseases and a much shorter life expectancy than we do because of that.

Since there is no clear data and everyone has different opinions, I say, why chance it?
I'd either move the garden or move the drain field.
Tom