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septic - could you fill a 1500 gallon tank in 10 months?

9K views 20 replies 12 participants last post by  denemante 
#1 ·
Hey all,

We have 2 adults and 2 small children using toilets, bathing, doing wash, etc. Just normal use. Any way that a family like ours might fill a septic tank in just 10 months?

I've had ongoing septic concerns since moving in 3 years ago. My saga revolves around the basement toilet "burping". And it always does it right around Thanksgiving when the temp starts to cool in Atlanta. It burps when you flush it, it flushes slow, and bubbles when other water is used in the house - but still works. The problem goes away in about February or March.

Year one - I had some guys out and didn't like what they had to say. I did nothing. Problem went away. Used system with no issue for a year.

Year two - repeat. I had different guys out, didn't like what they had to say either. Problem went away. Used system with no issue for a year again.

10 months ago - decided it was time to have the tank emptied since it's unknown when the previous owner did. Tank was full. Filter fine, fields fine. Glad I didn't listen to the first two guys in previous years who wanted me to replace the fields, etc.

But there was a missing T-valve/pipe where the main drain enters the tank. It's just a L-shaped 8-inch piece of PVC that makes a right turn down into the tank about a foot. It wasn't there. So the main drain just came out horizontally into the tank about 2 inches. When the tank was emptied - it wasn't in the bottom. The septic guy had no clue why/how it was missing. So they added one on.

They also said that a patio the previous owner added over the main drain line had pushed it down a bit. So waste wasn't flowing strongly downhill into the tank - that line was nearly flat, so sewage could get stuck in that run of drain line.

Guy said to tear up the patio, or use a hose to blow out that section when needed. And double flushing and running water would help "push" the stuck waste through into the tank.

15 feet from the tank in the patio is a washout. I open it, and can see waste inside. So that main line must in fact be full or backed up.

I'm again experiencing the same bubbling basement toilet and burping from it. But again, in past years, I did nothing and it just went away.

1. I wonder if enough weight of waste backs up in the line and finally blasts that one section clear eventually.

2. Or, the tank is so full it's backing up into the main drain (when emptied just 10 months ago?)

3. Most of you might suggest the field may be defective or bad so the tank can't purge. However - I have TWO separate fields. Previous owner added the basement bathroom so somebody talked him into adding a much larger field, even though that might not make sense - he did it. So I have a diverter valve and switch the fields about once a year. The previous septic guys said I'm super lucky - my fields were fine (filter was also perfect) - plus I have two totally separate fields just in case.

Using common sense, it just seems like that main line is a bit backed up under the patio (since I can see waste in the washout), and perhaps trickles into the tank vs. flowing. Like I need a giant plunger or something.

Anybody have any thoughts here? Should I rig some sort of 8 inch round pusher on the end of a flexible rod, and jam it down the overflow to see if I can push the waste through and solve the problem?
 
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#14 · (Edited)
Patio???

Something here does not make sense.

1. How deep is the main running from the house to the Septic Tank? The reason I ask is that pouring a slab on grade should have no effect on the main waste line whatsoever.

2. If the toilet, or any fixture burps, it is not properly vented. If it backs up, either the septic system is not working, (Clogged Leach Field)or you have improper slope from the house to the septic tank, and the solid waste is settling to the bottom of the main. This can happen with too much slope, as well as not enough. The slope has to be adequate to keep the solid waste suspended in the flow of water. If you have water saver toilets, pull out the baffles. They are the worst things ever invented, IMHO.

3. Hopefully, nobody in your house throws swifter pads into your toilets. These things can clog up a septic system.

4. There used to be those that said that if a septic system is designed properly, it will never need cleaning out. Now that we flush all kinds of stuff down the toilet that is not organic, that is probably no longer true. I use Dif in mine just to jump start the bugs once in while. The Septic guys say to pump your system every two years, but then they get paid to do it. The real answer is "It Depends"
 
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#4 ·
I stated this wrong. I know the tank fills in a week or so. What I meant is, is there any way it might need to be emptied after just 10 months?

Since I know I've got some sludge in my main line that leads to the tank, I'm hopeful that I can just clear that out with a hose or roto-rooter. Just remove the growing stoppage.

But if what I see in there is overflow solid waste from the tank - then I need to have the tank emptied.

But since the tank was emptied just 10 months ago, that would lead me to think the tank is fine....and that drain line is a bit backed up.
 
#7 ·
Your tank should be pumped every 2 years. The "T" they installed should be installed on the outlet side. Your drain line needs to slope a 1/4" per foot. Sounds like your drain line has a slope problem or roots. Have a drain cleaner come out clear the line & put a camera thru the line to check for problems. Make sure he gives you a copy of the video (no video no pay), or you can buy a power snake & snake the line out everytime you have a problem. You should have a cleanout inside the house. If not remove the basement toilet & snake from there.
 
#8 ·
Sure sounds like the leach feild has failed, or distribution box is messed up.
Where you there when they pump the tank? Did you see water rushing in from the drain lines to the leach field as it was being pumped?
As septic tank is always full of water.
It may have worked for a while because the tank and the drain lines where emptyed so the gray water had a place to go.
 
#10 ·
The topic of how often a septic tank should be emptied has been discussed repeatedly on this forum over the past three years, do a search and you will find numerous threads with wildly different opinions. I studied this question when I was the engineer advising my local Board of Health on septic matters. The most authoritative studies I located indicated that a carefully managed system could go ten or more years between pumping with no issues, and a poorly managed system may require pumping every year.

The key issue is the amount of organic material flushed down the drain. In a carefully managed household, very little organic material is flushed, rather the organic material is composted. The actual organic load on the septic system is then quite small, and the bacteria that naturally live in the septic tank are generally capable of breaking down the relatively small amount of organic material that is flushed into the tank, preventing adverse buildup of sludge and scum in the tank. But you can actual measure the buildup very easily, by opening the manhole cover, and inserting a stick with a rag into the tank. The tank is typically only about four feet deep, so a five or six foot stick is generally adequate. You can then measure the sludge buildup in the bottom of the tank. When the sludge reaches about 10 percent of tank depth, it is time to pump.
 
#11 ·
The topic of how often a septic tank should be emptied has been discussed repeatedly on this forum..............The most authoritative studies I located indicated that a carefully managed system could go ten or more years between pumping with no issues, and a poorly managed system may require pumping every year.
Suggested pumping frequency is somewhat location/climate dependent; here in AK the temperatures are so low that there is little or no bacterial action to reduce the volume of solids. For a typical household, annual pumping is recommended.
 
#13 · (Edited)
The normal, or equilibrium, water level in a septic tank is about 9 inches below the top. If the tank was just pumped, this level will usually be achieved in two weeks or less. No water exits the septic tank for the leach field before it gets to this level.

Then for each gallon of water entering, a gallon exits.

Normally it is not necessary to pump the tank unless much sludge and non-bio-degraded solid matter has accumulated, I would say to a third of the water depth (someone else said a tenth), or much grease (scum) has built up to fill the last 9 inches above the water level. In fact, pumping the tank out too often is just a waste of money unless the leach field has failed awaiting renovation and the role of the septic tank has therefore changed temporarily to holding tank.

If the septic tank is full to the brim then there is a problem downstream, in the leach field or lines leading to that, or at the septic tank outlet.
 
#15 ·
Based on everything here, I think the first thing I'll try is cleaning out the main. I have a washout in the patio about 15 from the inlet on the tank, so I'll try that first. Is there any basic product from the home depot I might use? I was going to try a hose. But if there is some flexible fiberglass rod with a ball on the end, maybe that would be better.

Next - yes, the basement toilet burping has been noted as a possible venting issue. It's strange that this burping happens when water is used elsewhere in the house. Also burps once when the basement toilet is used. Again, this only happens this time of year.

Worth noting is that the basement bathroom was subbed/pre-plumbed. The main house drain is 25 feet away from this bathroom coming down the wall and into the slab. So somewhere under the slab, they meet, become one, and go out under my patio to the tank.

Since it burps when other water is used in the house, common sense says there is some sort of blockage in the main after where they meet, and instead of the upstairs waste easily flowing out to the tank, somehow, it meet resistance and pushes the air in the bathroom drain back towards it, compressing the air a little, and causing that toilet to burp.

Or, it's creating suction as that waste does go out the main, and actually pulls on the air in the bathroom drain, with similar effect.

There's a studer vent on that toilet...
 
#19 ·
Sure could.
I just crawled out of my 1000 gallon septic tank. Tree roots were growing into the tank just barely, and same roots were starting to grow into the feed line to the tank.

I cut the tree down which was only a few feet away from the tank's cover.
Small tree only about 4" in diameter but if I didn't get to now it would really become a problem in a few years.

Your problem could be that or something like the others here have mentioned.

Kap
 
#20 ·
Venting

If your main line is clogged up, your toilet in the basement would overflow in short order. The rule for venting is that you have to have a vent within 48 pipe diameters. Either you have that or you dont. If you flush the toilet downstairs and it looks like the water is being pulled down at the end of the flush then it comes back up, your toilet is not vented. Burping, or gurgling signifies a lack of proper venting. You see this a lot when a dishwasher does not have an air break installed.
 
#21 ·
Hmmmm....when we finished our basement, I was particular about noting the toilet venting to the plumber who was doing some other work not-related to the septic/bathroom. We had been experiencing this burping issue before this - so I noted it to him - he claimed to be all over it - he extended the pvc toilet vent higher in the wall so it was up in a void open to an unfinished storage room and put a new studer vent on top.

If in fact my main drain to the tank doesn't have quite enough slope, I'm not thinking it's totally clogged. Rather, solids are sitting in it, slowly building up. Water is flowing over them, and perhaps at times, enough water flows through to completely seal-off that main momentarily - causing a vaccum of sorts.

Something else worth noting - when I open the washout - I can see water in there mixed with what appears to be TP. And that water level sort of pulses or waves or bounces rythmically - like it comes up 1/16th of an inch and falls like something is on either end pushing a core of water one way or another...
 
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