A friend of mine runs a martial arts studio where his concrete-floored office in the back is slightly below grade and floods every time it rains.

I assume that a proper solution would presumably involve re-leveling the floor to slope towards a central point, and then placing a drain at that low point. But the chance of this happening is zero-- it's a rental space and very low-budget and the landlord is not going to do anything. So it's up to my friend to figure out a solution. Today the solution is mop and bucket. Not good.

Are there standalone pumps that can be left on the floor that will suck up standing water? I assume a big difference between a standalone pump and a "drop in a hole" sump pump is that the standalone one has to be heavy enough on the bottom so that it won't tip over easily.

There's not that much water-- probably 10 gallons/hr in the heaviest storms, much less under normal conditions.

It doesn't need to be perfect, just needs to prevent flooding so he can get through a 90-minute class without mop duty.

Got ideas?


First off, your friend should definitely talk to his landlord about the flooding. Even if the landlord won't address it, it's possible your friend could be held liable for water damage from the flooding if he doesn't notify the landlord.

There are two big differences between the pump you need here and a normal sump pump. The first is that it won't be run submerged; most sump pumps (and many other kinds of pumps) need to be run submerged to prevent overheating. Second is that it needs to be able to suck up very shallow water, which generally means it needs to be self priming as well as needing a specially designed inlet and float valve.

Pumps designed for that kind of task are typically called a "puddle pump".

  • 2
    floor sucker pump seems to yield better results for non-commonwealth English, don't ask me why - puddle pump seems perfectly valid as a description, but most results are .uk or .au – Ecnerwal Dec 12 '14 at 20:31

Keep it simple, buy a wet/dry shop vac and suck up the water with it occasionally. Cost you about $60.


It's best if you can figure out where the water is coming from and try to stop it. A lot of times you can solve these sorts of problems easily and cheaply from the outside. Check the gutters and downspouts to make sure they are clear and divert the water at least 6' from the building. Make sure the ground is properly sloped around the outside. If there are paved areas around the perimeter, repair any cracks.

You said that the office was slightly below grade, is there a stairwell leading to it outside? Is there a drain in the stairwell that might need to be cleared? Could you put an awning over it?

Digging a hole through the slab to put in a sump pump isn't cheap and probably not something you'd want to do for a rental unless the landlord will reimburse the costs. You can get switches that detect water that will turn on pumps that don't need to be in a sump. Those types of pumps usually leave a small amount of water behind. 1/8" or 1/4" depending on the model. You also have to figure out how you're going to get the water out of the building which may involve drilling a hole in addition to plumbing.

The wet/dry vac Jimmy Fix-It recommended is probably going to be the cheapest/easiest option. Just need to keep items up off the floor in the areas prone to flooding to keep them from getting wet. You can prop furniture up on bricks and/or cinderblocks in those areas.

  • Shop vac is (very) loud and non-automated - cheap yes, easy, not really. If propping things up, "drainage mats" or "duckboards" are somewhat more tidy than cinderblocks unless the depth is absurd. Drainage mats (typical 1/2- 5/8") and a floor sucking pump (1/8" or less) should keep the water level below the mat surface. – Ecnerwal Dec 13 '14 at 19:14
  • @Ecnerwal shop vac is loud yes but can suck up the water quickly and get all of it compared to a floor sucking pump. You'd till need a shop vac to suck up what the floor sucking pump can't plus making access to get the pump draining outside may not be feasible in a rental – OrganicLawnDIY Dec 13 '14 at 19:28

The proper solution would be drainage tiles around the foundation of the exterior walls and proper grading, this way the water would never enter the space in the first place.

However, digging up the exterior of the house often isn't a viable option, so the next best thing would be an interior French drain that drains into a sump pit, along with a sump pump to remove the water when it reaches the appropriate level. This would actually be easier than removing and re-leveling the entire floor since you only need to remove the perimeter of the floor.

  • Well, yes, but good luck getting the friend's bad landlord to do this...and indeed, looking for a new place to lease is the ultimate solution from the renter's POV, I suspect. – Ecnerwal Dec 12 '14 at 20:41

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