When I was a kid, my folks’ basement flooded, so (among other things) my dad installed a sump pump. Simple enough, it sat over the floor drain (we lived in the country, no sewer) with a tube (I presumed) extended into the drain; a sensor would have the pump shoot the water out a hose and into the yard (where I always thought it would just pointlessly recycle back into the drain, but that’s not my question).
I now live in the city, and there is a sump pump in my basement that fires automatically. The thing is, the pump is in a 2’ hole cut into the foundation, some three feet below the basement floor. This is a part of a concrete cylinder that extends (as far as I can tell) some ten feet down (at least that’s where I see the water).
I can understand why the pump isn’t just set over a convenient drain, since all the drains are on the sewer line, but what is the purpose of letting a pre-drilled hole in the ground fill up with water and then pump it out? I thought the pump was needed when the water is “very close” to running into you basement from below, as an emergency stop-gap during a period of heavy rain and poor drainage?
Forgive my ignorance, but I clearly don’t understand the purpose of the pump, and that makes me a dangerous homeowner
Sump pumps should be set in a pit. The pit should be at the lowest point in the basement. Any water that gets into the basement fills up the pit. The pump should have its intake at the bottom of the pit and the sensor should trigger the pump to turn on when the pit is just about full. And the sensor should trigger it off just before the water level in the pit reaches the pumps intake.
This set up gives the pump the longest run time. It is unhealthy for a pump to turn on and off frequently, so the longer the run time the better. Pumps become very in efficient(or don’t pump at all) when they start to pull air in. Setting a pump at floor level doesn’t guarantee it will always have its intake below water,unless you think 2 inches of water across your whole basement is normal.
The idea is to let a certain amount of water collect in the sump before the pump turns on. The reason is to keep the pump running a somewhat reasonable length of time followed by a reasonable off period. This keeps the pump from cycling on and off all the time, which might cause the pump to wear out faster.
The sump pit also gives you a little leeway in case of a short power outage…which tend to occur in exactly the sort of weather where you need the pump working.
In the case of my home, ground water from all around the foundation is also diverted INTO this hole and then pumped out away from the house.
This hasn’t always been the case at my house, until I had the work done. Previously water just went down and sat in the dirt next to the foundation, where it soaked right through to the inside of the basement walls.
Now it drains down into some pipes before it gets to the foundation and rolls down towards the sump crock and then is pumped out all the way to the drainage ditch at the street.
FWIW my dad was also under the impression that the main point of a sump was to help you out if your basement got flooded. Now he knows (me too) that it’s to keep the basement from getting flooded in the first place.
And with a deep sump like you’ve got, you can do what some neighbors of mine did - the regular sump pump was about halfway down the pit, and immediately over the pump was a battery-operated pump. They had a deep-cycle battery on a trickle charger, so if there was a power failure, they’d still have a couple hours of pumping time available
And, in times of heavy rain, the two pumps would run in parallel (through separate discharge pipes) so that “last foot” between a dry basement and a mess had two pumps running to keep the water level down.
This Old House had a segment on a power failure backup sump pump. It was powered by city water pressure, if you can imagine. For every gallon of city water that flowed through the pump, two gallons of flood water would be pumped out. Your water bill may go through the roof, but I’m sure it’s miles better than having your basement flood.
When dealing with water, it is easier to give it an ‘easy path’ which you can control than it is to try and stop it.
An ideal sump pump is set under the basement foundation. All grading is done towards the sump pump, and a ‘french drain’, usually consisting of perforated pipes and stones, helps guide any water under the foundation and to the sump area, where it can collect and then be pumped out (ideally to an area far enough from the house that the grading outside keeps it from coming back in.
I think in my area it’s common to connect them to the sanitary sewer. I reached that conclusion by wondering why the heck the township actively encourages everyone to run their water gutter downspouts to more than five feet from the foundation. They say that it reduces sanitary sewer usage. The only way I can imagine that this is possible is by having the roof water filter down the foundation, under the house, and then make its way to the sanitary sewers via the sump.
It may be common, but I can’t believe it was legal in most places. Letting storm water into a sanitary sewer overloads the system and makes untreated discharges of sanitary sewer effluent more likely. It is at best irresponsible, and in any place I have ever resided against the plumbing code.
It’s probably against the code now. I know that here in Michigan there’s been a large push in the last 15 years or so to mandate separation of city and storm sewers. In my part of the state, we still have severe problems with sanitary sewers overflowing into Lake St. Clair during periods of heavy rain. I reason that existing connections must be grandfathered in, otherwise why would the township government just not mandate changing the connection rather than only advocating that downspouts end five feet or more from the house, and indicating that doing so reduces sewage treatment costs?
Now that I think back to my previous house, my pre-purchase inspector noted one of the downspouts directly connected to a drain (I don’t recall if it was sanitary or storm). He told me it was a code violation, but probably grandfathered in. That was 1951 construction; current home is 1984.
