I live in the Midwest. And as many of you probably know, the recent severe storms have left many here with flooded basements and ruined property. And this got me to wondering: *why don’t they simple make basement drains so that you can *shut them off ** in a storm, and then of course reopen them once the storm has passed? The rest of the drains in the house would be left open of course. But shutting off the basement drains–is that possible 
?
I would think that such a thing would not only be possible, but possible for the moderately skilled homeowner to do for himself. They make large plastic plugs, of course. Or just make the top part of the drain, just under the grate, a threaded piece of PVC, and screw in a plug when necessary. Hmmm… Can anybody think of a reason this wouldn’t work?
As far as I can see, all basement drains blocked off apart from a few (because some will leak, some people won’t bother, etc) will result in a large surge backing up the drains on the ground floor. Not fun. Only a WAG, though…
For various reasons you wouldn’t want to do that (if it was a good idea, I would think it would be standard practice). One reason is that ALOT of pressure will build up behind it and probably end up blowing it out. Anyways someone I know came up with a VERY good idea. She has a big piece of PVC pipe, the diameter of the basement drain and several feet high. Whenever she thinks the drains are going to back up, she puts the pipe over the drain (I don’t know the details of how it’s ‘mounted.’ As the water level outside rises, it’ll rise to the same height in the pipe. It won’t flow over into the basement unless it flows up over the top of the pipe. I don’t really care to get into the mechanics of it all right now, but a simple google search for “fluid dynamics” or hydrolics will probably pull up a decent explination of why it works.
My mother, who’s near Chicago, does the same thing - the floor drain in the basement has a lose grate / lid. When flooding, or more accurately, backed-up sewers, (curse that combined sanitary and storm system!) seems imminent, she just kicks the grate aside and stuffs in a section of PVC (?) pipe that’s a snug fit to the drain.
Doesn’t even have to be very long to keep rising levels in the sewer at bay - it’s about four feet from floor level to ground level. If it gets any higher than that, it’ll start flowing out of the street manholes first, as they’re slightly lower than the land around the house. Actually, the toilet on the basement level would overflow first. :eek:
It’s effective too. Even a quarter-inch of sewage in the house makes life miserable.
A lot of commercial properties have what are called back-flow preventers or “check valves”.
I’ve seen basement drains in some houses that have a sort of ping-pong ball type thing that was trapped in the drain. If the water backed up, the ball would float up and shut off the drain opening. I’m not sure how well they worked though.
Most houses around here have either sump systems or two seperate sewers leaving their houses, a storm and a sanitary.
…although “hydraulics” might be more effective.
You can (and some people do) out a “check valve” in a drain line to prevent backups. This is basically a one-way valve that works sort of like a trap door - sewage going out can push the door open, but sewage backing up into the house will force the valve closed. Unfortunately, they are trouble-prone - bits of string, hair, paper and other things not suitable for family discussions can foul 
the mechanism and allow leakage. Since maintenance of sewer lines is not a common hobby or pastime, most check valves are removed by plumbers to keep them from fouling drain snakes.
I forgot to add, “check valves” are basically a one-way door that hangs down and will swing in only one direction…away from the drain.
If you have a toilet or shower installed in your basement then the extension tube for floor drain idea won’t help much. It’ll simply ensure the water overflows in the finished part of your basement rather than the unfinished part.
Why do you say that. The tube won’t force the water out anywhere else.
No, it won’t force it out anywhere else. But if the shower drain is lower than the top of the extension tube, it will flow out there instread.
I have seen expandable plugs for floor drains that are threaded for a piece of PVC to be used as an extension.
The principle of the tube thing is that if the level of the flood reaches, say, 4ft above the floor of the cellar, it’ll still be contained within a 5ft tube. If there’s other plumbing in the cellar, then water will still reach that level and flood from there.
It will not flow out there instead . It will flow out there because there’s nothing preventing it. The tube installed elsewhere won’t change a thing. Water will rise to the same level everywhere, in the pipe and in the shower. If this level is one foot above your shower drain, it will flow out of the shower, whether or not there’s a pipe installed in your other drain.
Actually, if it had to be any consequence at all, the pipe in the drain would reduce the risk of flowing in your shower, because since there’s some water in your pipe the overall level of the flood would be lower. Of course, since the volume of water in the pipe is totally neglectible by comparison to the volume of water in the sewers, it won’t change a thing in reality.
Not necessarily. Let’s say there’s an unfinished part with a drain in the floor, and a finished part that’s one step up (because it has a finished floor installed). The finished part has a shower enclosure with a floor drain.
With no standpipes, a minor backup will flow into the finished part only. With a standpipe, it may flow out of the shower drain instead. This assumes two drains in the system. If there are other drains/outlets (say in a neighbor’s basement) that are connected to the same system, the diverted flow may go there, instead of out of the shower drain. It all depends on the relative heights of the drains and the overall capacity of the local drainage system.
Urg. …into the unfinished part only.
The plant where I worked has a 49 acre roof. The roof drains are periodically overwhelmed by heavy rains. If there’s a half-inch of rain in a short time, spectacular fountains of drain water come out of some drinking fountain drains. All the fountains have check valves, but some get jammed up with gunk. It was dumb to tie the roof drains into the sewage drains. It was cheaper, though, so they did it.
Many cities tie their street storm drains into the sewage lines. Besides flooding people’s basements, it also overwhelms the sewage plant. When that happens, raw sewage dumps right into the river every time there’s a big rain. It’s expensive to fix the system, but if we want to be able to eat the fish in our rivers and let our kids play there, we have to do it.
I’m afraid you’ve got it backwards. The standpipe would increase risk of flooding in slightly higher drains. All the incoming water has to do is fill up to a few inches deep in the standpipe before it can start flowing out the higher drain. With no standpipe, that water would have to fill the whole basement up to a few inches deep before it can start flowing out the higher drain. The basement cross-sectional area is a lot bigger than the standpipe’s.
So you have a 20x30 foot basement, a floor drain at the lowest point, and a second shower drain say 4 inches higher off in one corner, and flood water 6 inches higher than the bottom drain level. Put a 4 inch standpipe in the low drain, then the flood water will start rising in it, and when it’s 4 inches deep (after containing only 1/3 of a gallon of the flood water), it’ll start overflowing out the shower drain. Leave the standpipe out, and the water fill start filling up the lowest part of the basement through the low drain. The low part of the basement will hold ~ 750 gallons of flood water before it’s high enough to start overflowing the higher shower drain.
Not sure how fast the water flows into basements… but if it’s say 5 gallons/minute, it’ll take 2.5 hours before your chinchilla carpet gets flooded from the shower drain & rising floor drain tide sans standpipe , but only about 4 seconds if you’ve got a standpipe blocking off the “holding pond” that is the low area of your unfinished basement. You should be able to keep ahead of the former with a bucket or pump, but you’re screwed with the standpipe.
By the time the water rises to the full 6 inches and floods everything anyway, the storm might be over. You buy a few hours time with no standpipe letting the water flood the ugly part of the basement, but with one the water will almost immediately overflow the next lowest drain.
Two things are being confused here. Rising groundwater and rising sewage.
At my mother’s house, there is an unfinished crawlspace that’s the sacrificial groundwater holding pool. It has no sewer connections, but can hold approximately six inches of water. The standpipe for the floor drain is in a higher finished section, that ideally, will hold no groundwater or sewage. If the rising sewers get so bad to cause an adjacent toilet to overflow, the standpipe at least gave enough delay to start moving things to higher floors.
Didn’t see this covered above…
My house and many of the houses in my area have an access point to a shut-off value for the main sewer line that feeds into my basement. This allows me to manually disconnect my house from the sewer system during killer rains. When a storm delivers 4" or more, the storm sewers back up and flood the street. Some of the storm water makes its way into the sanitary sewers which in turn sends a flood of sewege back into the house.
I believe these access points are also useful for clearing out clogs or tree roots from the house’s main sewer line. I’ve noticed that neighbors get these access points installed when they re-run the house’s main sewer line.