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upmaroon 07-27-2010 07:38 PM

High water table
I live in the city far away from the lake or any body of water (like a creek). During a heavy rainfall last year, I noticed that my basement was wet (though not flooded, more like sweat) and the water seemed to come from the ground. There is presence of efforvesence on my basement floor but not everywhere. This did not happen again until last month after another heavy rainfall. You can see the floor was wet in some areas and it was not coming from the wall. I was advised that i probably need a sump pump. I had a sump pump installed but was surprised to see that my water table was very high. The clearance between the water table and the bottom of my basement concrete slab is only about 4 inches. Is this normal? My basement slopes down to the middle of the room with the difference in elevation from the end corner of the room to the middle (where we installed the sump pump) and which is the lowest point is about 1 foot. Beacuse the water table is high, the pump keeps going on and actually has saturated my back yard. I do not know where the water is coming from and I am beginning to doubt that this is the normal water table. Could it be that my weeping tiles are blocked or that there is a leaking main pipe? How can I tell? I don't think any of my neighbours have a sump pump and I am wondering whether I need one. It has not rained for 3 days but my sump pump is still running water out almost every hour. Even after 3 days of draining, the water always rises up to the same level. I live in Pickering and nowhere near a lake or creek.

(Unfortunarely my basement is finished).

Please advise.


oh'mike 07-27-2010 09:24 PM

If you indeed have a high water table--but it is lower than your slab--You can adjust the float--or raise the pump in the hole--so that the pump only runs if the water level rises above the normal water level.

Often a good pedestal pump is easier to make the fine adjustments than a submersible.--Mike--

upmaroon 07-27-2010 09:58 PM

Thanks for the reply and I am using a submersible pump. I have actually placed it on top of a concrete to raise the float. The plumber raised it high enough that I can't even close the lid properly anymore.

It still puzzles me that the water table is so close to the basement floor, just about 4 inches clearance. The house is about 20 years old but I moved in here only 2 years ago. In the 2 years since I moved in, I noticed the seepage only twice and only after a very heavy rainfall. I guess the heavy rainfall raised the level high enough to reach the basement floor. Did I really need the pump or should I have just fixed the areas where the water was going through?

oh'mike 07-27-2010 10:20 PM

If the water seeps in the cracks during times of higher than average water--then,yes,a sump pit and pump are a good idea. Think about a pedestal pump when that one needs replacing---

They are good for high water pits (easy to adjust)--Mike---

AllanJ 07-28-2010 08:15 AM

It is not unusual for the water table to be just a few inches below basement floor level. Over a period of a few days the water table will slowly go up and/or down depending on rainfall. If the basement floor is dry, you can leave the water level alone. But if at the same time the basement floor is wet, you need to take steps including operating a sump pump.

The sump pump must discharge the water far enough away and to lower lying ground so the water doesn't find its way back.

Do you have weeping tiles?

Weeping tiles must be connected to a sump pump pit or somewhere else that takes the water away via gravity flow.

Once you get the weeping tiles connected to a pit (if not already), the pump in the pit should keep the ends of the tiles as seen in the pit from being completely submerged.

daveb1 07-28-2010 08:26 AM

Are your eaves troughs clear?Down spouts spilling far enough from the foundation?Landscaping sloped away from house?Have the water tested for chlorine to determine if it is city water.

upmaroon 07-28-2010 12:29 PM

Thanks for the advise. Yes I do have weeping tiles and they were there even before we installed the sump pump. I am actually wonderig if they are clogged or blocked and contributing to the high water table at least in my house.

Great idea about testing for chlorine. Does it mean that if there is chlorine in the water, then it is automatically city water? When testing for chlorine, how much chlorine present will determine that it is city water?

daveb1 07-28-2010 02:34 PM

The presence of chlorine means it is probably city water.Your city water dept might come out with a listening device that sometimes allows them to hear leaks.If youve had lots of rain they'll probably say ground water right away.

AllanJ 07-29-2010 07:15 AM


Originally Posted by upmaroon (Post 476728)
I am actually wonderig if they are clogged or blocked and contributing to the high water table at least in my house.

Weeping tiles won't contribute to the high water table provided you don't pour downspout water in.

Weeping tiles will lower the water table in the immediate vicinity of the house if water in them is drained out and pumped away and the tiles never completely fill with water.

daveb1 07-29-2010 08:27 AM

Some areas allow connecting down spouts to weeping systems.Where do your spouts drain?

upmaroon 07-30-2010 12:14 PM

Thanks for all the responses. I took a sample of the water and had it checked for chlorine content. It showed no chlorine so I guess that rules out the possibility of city water. I had it checked by a pool equipment supply store and they used an actual machine to test it (not just a strip test).

My downspouts are not connected to the weeping tile. They are just directed well away from the house.

I have called a professional waterproofer to take a look. We only installed the pump almost 2 weeks ago and it runs regulary, maybe every hour and a half everyday causing water pooling in my backyard. It seems to me that this will keep going as I mentioned the water level seems to be just a few inches below the basement floor. If such is the case, does it make sense to connect the water discharge to the weeping tile outside and around the house which in turn is connected to the storm sewer? I can't have it discharging outside as it pumps continously even when it hasn't rained for 5 days. I can see an even bigger problem in the spring.

I have turned off the pump for a full day and and it did not overflow the sump pit basket. That gave the backyard time to dry up a bit. However as soon as I turned it back on, the the pump kicks in at shorter intervals until it reaches its normal rate of about an hour an a half.

Any ideas on what else to check is greatly appreciated.

Scuba_Dave 07-30-2010 12:33 PM

I have a high water table too
My pump used to run a lot in the Spring
I adjusted my pump so it only turns on when the water is abolut 2-3" from the top of the pit
I also graded around the yard & directed some downspouts up to 20' away from the house

I can have water in the sump pit for a month at a time
No sense trying to lower the level of ground water - will not happen
...unless you are in a shallow area where water is trapped by clay/etc
Then the water needs ot be pumped beyond the "trapped" area
My sump pump pumps the water to a drain that leads it over 40' from my house

Daniel Holzman 07-30-2010 02:59 PM

You mention that the pump has saturated your backyard. This suggests to me that you are draining the pump into the backyard, which is not a good idea, since it sounds like the water you are pumping into the backyard is draining back into your sump pit (this is known as short circuiting). You need to pump the water FAR AWAY from your house, ideally into a storm drain if permitted by the city, or alternatively onto the street if you cannot connect to a storm drain (assuming that is acceptable to the city). Merely pumping the water back into your yard will not help, the water simply drains back to your pit.

AllanJ 07-30-2010 09:25 PM


Originally Posted by upmaroon (Post 476345)
It has not rained for 3 days but my sump pump is still running water out almost every hour. Even after 3 days of draining, the water always rises up to the same level. s.

Starting over almost from the beginning of the topic and discussion.

After letting the pump run every hour for several days, has the basement floor stopped getting wet?

If the floor keeps getting wet, then you need to do yet something else. Right now you took the first step, installing a sump pump where none had been before.

The water table might be two or three inches below the basement floor level but sometimes water wicks up through cracks or even through the concrete slab iself and makes the floor wet. It is possible that just keeping the pump going, draws away enough water that none seeps up to the basement floor.

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