Small yards and proximity to septic system

[backyard]

I've often thought about how we all grow vegetable gardens in our back yards but I never heard much about where in the back yard a garden should be.
Where I live the properties are roughly 75ft wide x100ft deep with the houses all about 30x30 in the center of the lot and driveway down one side. There is no city sewer here, only septic tanks and cesspools, often with multiple cesspools and a yard wide field drain at the end of the system. In most yards the system spans down the center of the rear yard and spread out full width on both sides.
1/2 of my back yard is septic system. The entire rear 1/4 of the property is field bed with a cesspool in the middle, the very center of the rear yard has the first cesspool, and the septic tank is a 500 gallon concrete box right next to the foundation in the middle. The system splits the yard in two right down the middle and then drains off to each side in the rear over about a 75 w x20 ft area along the rear property line. (Some houses here have one cesspool and the entire yard is field drains.

The people here before me planted their garden directly above the last cesspool.
I had two problems with that, one its over the cesspool, and two when you water the garden you put water down into the cesspool which you eventually have to pay to empty.

I put my garden behind the house off to one side, its on the far side of the septic tank and first cesspool with about 15 ft in between or so.
The house next door's driveway runs just beyond my garden, and their septic tank is roughly 30ft beyond my garden. Their property is curbed so there's no runoff toward my place, its directed out back into a field.

The entire neighborhood is below a run of high tension wires next that lead to a sub station behind these houses and beyond that the rear of a supermarket beyond a short patch of pine trees. The access road for that substation runs in between as well, a road maintained by the county by spraying it heavily with weed killer, but its down hill from my property by about 5 feet, and a good 8ft below the garden level.

I've considered making the garden bigger but really never liked the idea of getting too close to the septic system, not for the roots but more for the more obvious reasons.

How far is safe from a septic system?

 

[Oliver Buckle]

It depends a bit on how well the system is working and if it is emptied regularly, ideally it is safe by the time water comes out. Does it smell? That would be a good indicator. Adding water by watering above it shouldn't be a problem, that's not what is being removed, it's the solids that don't run off.

 

[Esther Knapicius]

We have a septic tank. Actually built an addition that one corner of it is 4 feet from it. I actually use the location of the septic tank to the benefit of my plants/shrubs. As it gives off some heat, the ground under is warmed some compared to other parts of the property there by a plant with less zone that I want can be safer in the winter in that location. 38 years now no issues. we have it pumped out every 3 years, and the company says all is well.

 

[Meadowlark]

That's a good question.

My septic system at closest point of garden separation is 50 feet and it is increasing after that. Never has been a problem.

I did a quick check with my AI and it said:

"A safe garden should be at least 10–20 feet from the septic tank and 20–50 feet from the drain field, with edible plants kept on the farther end of that range. This distance protects your plants from contamination and prevents roots from damaging the system."

 

[yardiron]

In most of the area where I'm at every house has a septic system, water wells are usually on the furthest part of the property from the septic system but that often means its closer to your neighbor's septic than your own. Mine was well in is my basement below grade, and 75ft deep. Its not drinkable, none of the water in the area is but mostly due to high nitrates from years of farm run off.
Water purification systems clog pretty fast here too. Lots of sediment and iron, it gets run though a water softener system which used a mix of fiber, sand and salt, then four 30" long charcoal canister filters that get replaced when the pressure drops showing a restriction. They still say don't drink the water.

The septic system takes up the whole back yard other than where the shed and garage sit, I plant between the she and garage. The area above the field bed is too shallow to plant in, the system is just slightly below the surface.
The nearby town has sewers and they stalked about connecting to them here but they wanted $40k per house to connect which got voted down many times One or two houses on the road behind me connected and they had to install an macerating pump to do so since its a high pressure sewer line. The one place had a check valve fail once and it filled the entire basement, and much of the house with raw sewage. I'll pass on that.

Most septic systems are at least 4ft below grade, with only pump out access at the surface. A septic tank is sealed, so fecal waste stays in the closed tank until it breaks down and flows from there. If system is working as it should, there won't be anything to pump out. In fact, pumping out the system can take away the needed bacteria that makes it work.

I pumped my cesspool out during after Hurricane Sandy, which flooded the area enough to raise the ground water about 8ft or so. Like most homes in the area the cesspool is deep, down into first water about 25ft down. The general rule of thumb is not to draw your drinking water from first water if its within 75 ft of a cesspool. I opted to go much deeper since there was no way to be 75ft away.

As a kid, most planted right over their cesspool since it fed nitrogen to the plants and gave them a constant source of water. Gardens then always looked fantastic because of it. An adjacent septic system was just seen as free fertilizer.

 

[backyard]

My only concern is if someone's system overflowed and thus traveled down hill. Theoretically if the neighbor who is a few feet higher than me had a tank clog or overflow, that could certainly spill raw sewage on the surface, although it would likely run out to the street not yard to yard.

The new systems they install are built above grade, the tank lid is set above the field drain level by several feet. What you end up with is a large plastic septic tank that looks like giant barrel, that sits proud of the surrounding ground by several feet, which they generally mound over the top of leaving the lid exposed. But that lid seals tight.

The biggest concern I'd have is fecal bacteria becoming an issue with so many septic systems so close together in small neighborhoods. Its one thing when homes are hundred of feet apart but in much of the suburbs they tend to be only 10 to 20ft apart.

With all the issues these days with tomatoes and various bacterial spotting, it makes me wonder if proximity to a septic system can contribute to the issue.

 

[Oliver Buckle]

With all the issues these days with tomatoes and various bacterial spotting, it makes me wonder if proximity to a septic system can contribute to the issue.

I once worked with someone who had once worked on a sewage farm. He told me they had a bit of spare land and in Spring would run off a bit of raw sewage onto it and let it dry out a bit, the tomatoes would grow themselves.

 

[Ruderunner]

I'd be less concerned about the bacteria than chemicals. Laundry detergent tends to have high phosphorus for example. Many cleaners will knock out the bacteria in the system, the reason why folks sometimes have to add bacteria to keep the system functioning properly.

If you have access to the distribution boxes for the laterals you can get a sample tested.

 

[Esther Knapicius]

"A safe garden should be at least 10–20 feet from the septic tank and 20–50 feet from the drain field, with edible plants kept on the farther end of that range. This distance protects your plants from contamination and prevents roots from damaging the system."

Interesting-----tell that to the big tall tree we have roughly 6 feet from the corner of the tank. Tree was there when we moved in.

 

[backyard]

That's a good question.

My septic system at closest point of garden separation is 50 feet and it is increasing after that. Never has been a problem.

I did a quick check with my AI and it said:

"A safe garden should be at least 10–20 feet from the septic tank and 20–50 feet from the drain field, with edible plants kept on the farther end of that range. This distance protects your plants from contamination and prevents roots from damaging the system."

That's likely not possible in most yards here unless we put the garden in the front yard, where its not allowed to be. Only grass and shrubs may be grown beyond the frontal most part of the home.

Most rear yards are nearly 100% septic system, the houses are 30ft wide, the septic tank which is usually 1,000 gallons, is at the rear in the center of the house, 15ft beyond that is a cesspool down to first water for liquids, many have a second cesspool 15 feet beyond that, again, down to first water, with an array of 4" field drains running off that tank at about 4ft below the surface or depending on the height of the source. Yards are 75ft wide, a 16ft wide driveway runs down the left side of every yard front to rear with a garage or shed in the left rear corner. The houses sit 35ft rear of the curb, with 10ft to the right property line. There's a 5ft buffer to the front and rear that can't be used and 10ft to the left of each driveway. The yards all slope south by 12" per 75ft. each yard is flat and terraced about 8" at the driveway line either with a short slope or curb along the driveway.
The area to the right rear or along the rear right side of the driveway are the only areas where there' no septic below the garden areas. Most put their garden along the driveway, but that means it takes the runoff from the asphalt and road when it rains, and if they spread rock salt all winter, the garden suffers from it all year.

I have mine on the right rear, about 15ft to the right of the septic tank, along side it not down from it. But of course, there are 75 other tanks up the street from it every 40ft or so in each yard.

I've often wondered if the septic situation has anything to do with the bacterial spotting that's such a problem with Tomatoes here? Anthracnose seams to be the culprit and it shows up in early July here every year, I've gone so far as to remove all the soil down 6ft and replace it with fresh top soil using a backhoe but the problem persists and has for years.

The immediate neighbor has their garden directly over their septic tank. The vent is in the middle of the tomato plants. When it overflows, they say its free fertilizer. They did learn not to plant directly over the lid, in fact they raised the lid using a chunk of concrete pipe so they lid sits proud of the ground a bit. They dump all their water into the septic tank, washer, shower, and all. It overflows several times a year. They're garden is always a mess, sick, barely alive plants.
Most homes here have gray water drains that put the gray water out on the surface to water the grass.

My one rain gutter drains through the tomato garden, but I dug a troth to keep it from ever washing out the plants. I also put a tap off the gutter to save about half the water in a tank I buried just beyond the garden, a 500 gallon heavy plastic tank with a submersible pump for water when we get drought restrictions.

 

[Meadowlark]

Interesting-----tell that to the big tall tree we have roughly 6 feet from the corner of the tank. Tree was there when we moved in.

Presumably, no one eats anything from that tree.

 

[Martin Mikulcik]

@backyard

Do you use raised beds? I'm not a big raised bed fan (because hills and ridges are basically the same and easier to scale) but they could help you a lot, especially if your soil doesn't drain very well

Also if your space is quite limited you might not be getting enough sun. Tomatoes want to be out where we would sunburn all day long and buildings can block more than you might think.

You might also consider mulching the tomatoes with grass clippings, it might keep the fruit cleaner from rot. That's just a theory I've never studied it

If your septic system is working you should be good to go unless you're putting arsenic and heavy metals and such in it. If it's overflowing, sounds like a drainage problem, hence the raised bed. And good luck with the e coli

 

[Oliver Buckle]

@backyard, If there was that much septic stuff about my yard I would be getting some big containers.

 

[backyard]

One neighbor did that, he was concerned about the fact that his used to be a potato farm up until around WWII, when the family that owned it realized that their two sons had decided to become priests after serving in the war, they sold off the farm in lots.

About 1/4 of the owners here are related to the original families that built these homes. The one across the street is not, they bought it after the couple there passed away about 25 years ago.

They were concerned about the use of manure as fertilizer in the past the were afraid of the possibility of heavy metals or other contamination over the years so they went out and got a trailer load of used railroad ties, (treated with creosote and arsenic salts), then had four triaxle dump truck loads of 'clean' farm soil that someone was selling and 150 bags of peat moss from a Canadian source, and bags of fertilizer from the dollar store that says from China.

They stacked up the greasy black railroad ties to form raised beds about 3ft deep, then paid a bunch of illegal aliens to fill them with the mountain of dirt they had dumped in the side yard. The one guy who was working there was showing me the stuff they were finding in that clean soil, after filling four raised beds, out of about 80 total, they had filled a 20 gallon barrel full of spark plugs, used brake pads, wet wipes, condoms, needles, razor blades, and countless bones and rusty bits of metal.
That clean farm soil must have been from a former junk yard or landfill. There was enough bits of broken asphalt in that mess to pave half their yard.

Somehow none of that bothered them and they grow their garden in it yet today. Things like needles and condoms still surface from time to time in those beds. Not to mention how nasty railroad ties are. To top it all off, they go to the next town over to get free fertilizer from the sewage incinerator there. They would rather grow food in all the crap that gets cooked into that brown dust, heavy metals and all than risk the fact that the ground was once used to grow potatoes with cow manure and chicken manure as fertilizer.

For years the solid waste treatment plants all said the 'free' fertilizer was not for food crops, but they removed that warning when it started to pile up.

The fact that the ground is used to dispose of sewage here isn't the part that bothers me, in the older systems the sewage was dumped below ground, deep below ground. now with the new systems the tanks have to contain all the solids and disperse the liquids at the surface. That along with the fact that the newer style above grade tanks spill raw sewage when they overflow and rain washes that downhill.

 

[Meadowlark]

...The one guy who was working there was showing me the stuff they were finding in that clean soil, after filling four raised beds, out of about 80 total, they had filled a 20 gallon barrel full of spark plugs, used brake pads, wet wipes, condoms, needles, razor blades, and countless bones and rusty bits of metal.
That clean farm soil must have been from a former junk yard or landfill. There was enough bits of broken asphalt in that mess to pave half their yard.

Similar experience here (decades past)...on delivered mushroom compost. Needles, condoms, and worst of all medical waste...never ever again