How to prevent sewer backup into basement?

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If sewage starts to back up into the system, anyone have any ideas on how to keep it out of my basement?

-- Beans (drpete00@hotmail.com), December 14, 1999

Answers

I've heard of such backups occurring (pumping stations going offline.) I intend to plug the drains in the basement with test plugs (in the plumbing section.) The basement toilet (which we rarely use) will be plugged with a nerf-type football with a sandbag on top.

A sibling years ago had a local pumping station go offline - the sewer water backed up into the one drain in the basement - a washtub - until almost the top. It got close to the top, the pumping station came online, and the level went down. He had no damage.

His neighbor, on the other hand, who had a toilet & lower drains in his basement had a couple feet of sewer water in his basement. Major mess. I don't consider a sewer backup something I want under any condition, hence I've already got what I need to plug the drains.

I believe this is something you will have to address *before* it happens - once it starts backing up, you're probably SOL. I intend to leave the plugs in place for however long I feel comfortable about the power supply - even most of the year 2000...

-- Ford Prefect (bring@your.towel), December 14, 1999.


I have been wondering about this myself. I figured I would plug up my sewer drain in the basement if the power went down. I don't know if this is going to work, and was wondering if I need to plug all drains, sinks,showers, bath tubs ect. Dose anyone out their have the answer?

-- Gambler (scotanna@arosnet.com), December 14, 1999.

Did you guys check in the Prep forum? I seem to remember seeing something about this- some kind of backflow valve you can have installed in your sewer line- but it seems a bit late now for that sort of thing.

-- ldeeds (ldeeds@kumc.edu), December 14, 1999.

Why would sewage from a municipal sewer system back up into your basement? It will back up into the orifices that feed it(sinks, shower/bathtub drains and toilets. Most homes connected to municipal sewer lines have an in-ground cleanout. Find it(my sewer co. located mine) dig until exposed and open the cap. Sewage will run out into your yard but not into your home.

-- Get Real (gaf@mindspring.com), December 14, 1999.

I agree that it will back up into what feeds it - and we happen to have a toilet, shower, drains, and sinks in our basement. If you have no such drains in your basement, no worry. Our sewer line is pretty low for digging outside at this point (and the ground is frozen regardless.)

-- Ford Prefect (bring@your.towel), December 14, 1999.


Get Real, think 'floor drains'. Usually connected to muny sewage systems. They would flood the floor first. Now think about your sewer clean out for a second. I'm understanding that you dug a pit to expose it, correct? I agree that the pit would fill first, but it wouldn't be the only outlet to fill. As soon as the pit level reached the level of your interior drains, they would inturn become the low point for the sewage water, and would start to fill. Both pit and drains would then fill at the same rate. Remember, unpressurized water is self-leveling. It will always find the lowest point. JMHO.

-- Ninh Hoa (tech@univ.now), December 14, 1999.

A few years ago we ahd so much rain the pumping stations couldn't handle it. everyones basement flooded with raw sewage. 5 feet deep in mine. The worst mess i ever tried to clean.

Fema paid for an anti backflow valve to be installed inline. about 2300 bucks x my whole neighborhood.

-- once bitten (twice@shy.mess), December 14, 1999.


FP...

.....There is a ball-valve that can be purchased at most building supply or plumbing supply houses. Which one you would need would depend on the size of your pipe; some newer pipe styles have threads that this can screw right into.

-- Patrick (pmchenry@gradall.com), December 14, 1999.


"The basement toilet (which we rarely use) will be plugged with a nerf-type football with a sandbag on top."

.......... brings up a matter that I've never seen addressed on any of the "sewage backup" threads, which is: how much FORCE does a backup have? Is a single sandbag (20 lbs? 30 lbs?) sufficient? i.e. sounds like not that much force. If this is the case it would not be hard to blockade all backflow points with a bit of weight on top of the (whatever... nerf-type football -- whatever that is...)

-- alan (foo@bar.com), December 14, 1999.


I will apologize in advance for the length of this post, but feel it contains important information gained from first-hand experience.

Warning: E. Coli and other bacterium and virii found in untreated waste water can be DEADLY!

Under no circumstances should one allow raw sewage to simply pour out of an uncappeded clean-out. Those walking in the overflow and/or its' residue will track it into your homes, and once embedded into carpets, rugs, etc ... the various colonies will flourish and multiply.

An inherent problem with the installation of a sewer shut-off valve is that; if the system goes offline but remains usable (i.e. not backing up) and you turn off the valve, you will be unable to use the system.

A better solution, is to incorporate a 'flapper' valve between the ball-valve and your home. The flapper valve has a ridge running aound the circumference of the joint section with a circular plate hinged at the top. This plate should be oriented on the output side of the valve (i.e. on side opposite your house). Waste water can exit from your home, but no back flow can occur ... the backpressure closes off the valve. THEN ... when your neighbors are complaining about backup into their homes...you simply close the ball-valve. Back-pressures in excess of 200 psi can be safely handled this way. The sewer pipes outside your home will fail before the ball-valve will. The 'good' thing about this (if there is one) is that the waste water will be underground and less likely to be carried into your home.

Installation of these valves in a basement should be done such that the ball-valve is as close to the wall leading out of your house as possible. Minimizing the likelihood that, in the event of sewer pipe failure, the waste water will fill the basement.

If installing outside ... you should run an access pipe ( cheapest route - irrigation tubing ) from ground level down to the valve. A good way to secure the bottom is to acquire a 'straight Tee' the same size as the access pipe. Cut a slot along one side of the tee (one quarter of the circumference of the straight thru portion of the Tee extending from the side center line, down to bottom) so that you can slip it over the sewer pipe and valve (you may have to notch upwards towards the elbow connection part of the tee to slip the valve thru) then glue the access pipe to the top of the Tee. The 'shoulders' of the Tee will rest on the sewer line to support the access pipe and prevent it from moving out of alignment with the valve. Cut the access pipe off approximately 2-3" below mean ground level and slip (do not glue) on an end cap. Fill in the hole, ensuring that the access pipe stays vertical.

To activate the valve ... acquire a piece of steel water pipe approximately 3 feet longer than the access pipe. At one end thread on a Tee handle consisting of a Tee and two 4 inch or so 'nipples.' On the other end take two #10 or slightly larger nails. Cut off the heads of the nails and using 2 water clamps, clamp the nails to the pipe. Ensure that about a half of an inch or so of the nails extend past the end of the pipe. NOTE: If the are too long they will hit the side of the valve and not completely operate the valve. You might want to build and adjust the 'Valve Tool' prior to installing the valve underground to ensure correct operation.

One other note: a favorite 'trick' of mine ... when I have to dig thru frozen ground ... is to build a small controlled fire and allow it to heat the ground. This will melt the ground sufficiently to allow you to dig below the frozen surface layer.

If I can be of any other help, please let me know.

-- hiding in plain (sight@edge. of no-where), December 14, 1999.



A couple of forgotten points ...

should have been 'uncapped' NOT 'uncappeded' LoL :-)

The access pipe should be 3 to 4" in diameter. Running a line of glue along the top of the sewer line to hold the Access Tee is optional .... just remember that if you should ever have to replace the valve, the glue will require that you replace the Tee and some of the sewer pipe on either side of the valve as well. The shoulder created by the Tee should be sufficient to hold the access pipe in place.

The diameter of the Valve Tool pipe should be the same, or 'slightly' larger than the width of the handle of the ball valve.

After filling in the hole, you may want to place a piece of scrap plywood - 1' square or so - on top of the cap and cover with dirt. A 3 foot piece of rod, probed into the ground, will allow you to quickly and easily find the piece of plywood when needed.

Reason for leaving the cap 2-3" below ground level - think lawnmowers ... :-)

-- hiding in plain (sight@edge. of no-where), December 14, 1999.


If you live with 1/2 mile of a pumping station that fails the sewage will back up into and fill all of the basements. The "churney balls" or test plugs are only good for a pressure of about 25psi. The methane gas that would build up behind these would shoot them out of the drains like a rocket. The shut off valve described in the above post is the only effective way of holding back the sewage.

Call your city hall water department, and find out where the pumping stations are located at in your city. If you're over a half mile from one, I wouldn't be concerned because all the homes between you and the pumping station will get the flooding. Ask your water department if they have contingency plans such as generators to run the stations manually. Ask if personnel will be on duty during the rollover in the event you lost electricity. They should be able to give you these answers.

If your neighborhood is flooded with raw sewage you won't want to stay there anyway. The health concerns of being surrounded with this are enormous.

-- LOON (blooney10@aol.com), December 14, 1999.


I asked a waste water plant operator if a toilet could back up if the lift pumps failed. Only if the toilet is below street level, I was told. Sewage will overflow at a manhole, as in the Tillman spill. Toilets in a basement are often below the street level. The operator suggested the use of a "pig" (not a real pig). It's a bladder that is flushed down the toilet (about three feet). It has a tube and a valve connected. The bladder is inflated with a bicycle pump to around 80 lbs. psi. This will prevent raw sewage from backing up in a toilet. Since I don't have a basement, I haven't purchased any pigs. I believe they can be purchased at a plumbing supply. I wouldn't trust a nerf football and a sandbag.

-- Michael (mhgentry@prodigy.net), December 14, 1999.

Great suggestions - will check into the inflatable "pig" and call about the pumping stations tomorrow. Viele Danke!

-- Ford Prefect (bring@your.towel), December 15, 1999.

I discussed this question with my city's director of public works (he was the only one in the office after hours). He says that sewer systems are designed, to the extent possible, to carry water away by gravity. This makes sense: gravity always works and costs nothing, so a more complex routing would be worth the investment. Pump stations are used only in places where they can't make it work with gravity. This city of 100 square miles has about 40 pump stations, each typically handling a block or so. My location works entirely by gravity, so he *assured* me that a power failure would not cause a backup. In the whole year of 1999, this discussion was the one enouraging moment I've had. I suggest that any of you get similar information. Ask to see the map of the system, which shows the elevations of all the key points; find out where the pump stations are. From what my guy said, you either do or don't have something to worry about: it's either gravity or it isn't.

-- Christopher Brewster (brewsterc@excite.com), December 15, 1999.


A little story about a sewage backup we had. A few years ago a large willow oak uprooted in the planting strip at the street in front of our house. This was caused by a leak in the city water main. It took two days to fix the leak in the 8 inch water line and in the process our sewage line from the house which went under the water line was also broken, but no one knew about it. We had a monster hole about 20 feet long and 10 feet wide at the street and the first thing they did after repairing the pipe was to fill the hole with washed gravel.

Dirt was placed on top of that and everything appeared to be ok for a couple of weeks. Eventually the hole with gravel filled up with our waste water and the only recourse for the waste water "etc." from our house was for it to start to back up the pipe. We first noticed the problem when we would flush the upstair toilet and water and the "etc." mentioned above all overflowed in the house. Had we put some type of nerfball down that toilet the water would have just come out of the next lowest vent which in this case would have been the kitchen sink I think.

Certainly it is an excellent idea to think about these things before they happen so one has a game plan.

Good post.

jack mcneary

-- Jack McNeary (jmcneary@arborman.com), December 15, 1999.


Oh crap!, something else to worry about.

-- Bubba Smith (duck&cover@tshtf.com), December 16, 1999.

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