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We bought our house in December of 2015. House is situated at bottom of the slope (backyard is slopping towards the back of the house not very steep - but still negative slope). House has sump pump pit and drain tiles are opening in sump pump (roughly 8-10" from the top top the floor). Sump pump outlet and downspouts are tied to separate 4" PVC pipe and releasing water close to city storm system - roughly 20-30' away, towards the front of the house. On front and sides of the house foundation, ground is sloped properly (at-least for good 15' to 20'). Backyard is sloping toward the house and there is drainage grass swale (in backyard) which runs may be 10' feet from the foundation and goes to side of the house and water is released toward the front of the house (around city storm system). There is also positive slope from foundation back wall to drainage swale.

After heavy rain, our sump pump runs quite frequently, may be almost every couple of minutes when rain is falling and this continues for next 3-4 days. Also, I see water puddling in the swale and it stays there for few days - swale in the backyard doesn't have steep grading - its almost flat to very gentle grading (towards the city storm system). Currently basement is dry and I don't see any water seepage (I do see efflorescence on wall where it meets basement floor). Sump pump has battery backup but I'm bit concern that if we lose power for extended time during storm then battery backup or generator may not be enough for supply power to sump pump for long duration (since our street is small we get lowest priority when power is lost - according to neighbors, during last storm it took 5 days to restore power on our street). With sump pump running with this high frequency - I'm sure that basement will flood during outage (and basement is semi finished).

I called few basement and landscaping contractors - and got varying opinion from them. Seems like all basements contractors wants to sell french drain system (where they install french drain from inside of the basement) - I'm not sure if that would help me. Landscaping contractors - not confident that they can increase the grade in the swale significantly to alleviate water standing or few thought it may not help at all. Cost to redoing swale is significant and comes without any warranty (wrt improving sump pump situation). Few landscaping contractor thought outside french drain may help with standing water in swale but may not improve anything wrt sump pump running frequency. Some suggested catch basin boxes to address this issue.

Also, 3-5 days after rain - sump pump do not run at all. Soil in our area is clay and water absorbency is not good. Whole backyard and area around the house has lawn and very minimal plants around proximity to the house.As far as I can tell, my next door neighbor's sump pump runs vigorously as well.

My questions are:
1) What system do you experts think will works best for my situation? Inside french drain, outside french drain, swale improvements, catch basins or any other bright ideas?

2) Generally water in sump pump pit stays almost half way to the drain tile opening (sort of point of stabilization). That's how previous owner set the sump pump trigger point. If I bring level below the drain tile opening then sump pump keeps running and I can see drain tile dumping water in pit as soon as its being empty by the pump. Only time I see water level in pit falls below the drain tile is during no rain for extended period of time (almost like drought situation).

3) Could this high water level around basement deteriorate foundation and footing? This house is 16 years old and I don't see cracked floor or any issue with foundation walls or settlement issue. Basement is very dry and I don't smell moisture or anything in the basement. According to previous owners basement was never flooded (but they never mentioned me high running frequency of sump pump). Basement structure withstand this issue for for past 16 years without any issue (which I can tell)- so may be am I overthinking this situation?

4) Few landscaping contractor recommended outside french drain - but not very deep (may be 10-12" deep from top) and they can connect it to exiting 4" pipe carrying downspout water. Do you think its good idea? Way the slopping around the house is - very deep french drain is not a possibility (deeper than 2 feet french drain will not see daylight at exit).

Sorry about such a long post but I wanted to detailed enough for your expert opinion. Thanks in advance.

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    "I got lots of opinions from experts but I don't like them so i'm asking random people on the internet." <-- not a good way to start. I'll answer your specific question about sump runtime: so long as there's water in the ground higher than the sump's cut-on switch level, the pump will run. that's what it's supposed to do.
    – Carl Witthoft
    May 8, 2016 at 12:37
  • Thanks for your response. Issue with so called experts is, at the end of the day they want to sell you something. And also I'm getting lots of conflicting advice from them. While "random" people on Internet not selling me anything and I can learn from someone else's experience. And if nothing else I can educate my self with different options and that will help me talking to contractors. I learned great deal of stuff from this website and being first time home owner you don't know lots of common stuff right away.
    – bob
    May 8, 2016 at 13:39
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    It sounds like there's already a drainage system in the basement, so adding a french drain inside doesn't make sense to me. If the pump float is set below the local water table, the pump will run forever. It sounds like maybe the water table is coming up to the level of the drain tile, so if the float is set below that the pump runs continuously. Hopefully the exterior of the foundation was properly protected to reduce the chances of water infiltration, but you didn't mention that in the question.
    – Tester101
    May 8, 2016 at 15:00
  • It's quite difficult to give advise, without actually being on site (even though you've provided a lot of details).
    – Tester101
    May 8, 2016 at 15:01
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    I agree with tester that an additional inside French drain would not be worth the cost and it may create leaks since the cement will be cut. With only a 2' outside French drain to the street it may not help a huge amount but it would help drain the low area and reduce some of the water making its way to the pump. This would be an easy DIY if you rent a ditch witch to dig the trench. I use the perf pipe with the sock on it to reduce ingress of dirt and sand. + for the amount of detail in the question.
    – Ed Beal
    May 8, 2016 at 16:57

1 Answer 1

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Obviously, the soil needs to be graded away from the house (in the back yard). If that means you need a retaining wall, then you need a retaining wall.

Regarding the swale, improved drainage sounds helpful. The real question is, why isn't water shedding (what is the real issue)? I've had swale issues, and the problem in those cases, was not with my swale, but the neighbors'... so water backed up in my yard. In such a circumstance, you can talk to the neighbors about the issue, ask them to fix it, offer to help, and/or sue them for damages.

But if the neighbors aren't to be blamed, then another alternative to keep the grass cut very short (grass slows drainage). Or you could check into a trench drain (concrete ditch). This is just another option that I didn't see mentioned, although it may not be your best option. As Tester101 pointed out, being there to see the issue is probably necessary.

Regarding power outages, gasoline or propane generators are the most reliable answer. A moderate generator should be enough for a sump pump, the fridge, and should keep the toilet flushing too. As you know, the drawback with a battery bank is that once it discharges, then you don't have a simple solution, like getting more gas.

Edit- Here's a possible way to use a retaining wall to increase the grade away from the house.

enter image description here

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  • Thanks for your detailed response. Soil is graded for about 8 feet from back foundation wall in backyard (may be two inches over 8 feet). And at the end of that grade - swale starts. Two landscaping guys looked at this situation and they said swale needs to be steeper for it to work properly - but issue is swale runs to the front of the house and that distance is about 65-75' but they can't go much steeper at over this distance otherwise - end of the swale (at the front) will go below side walk level and water will not exit to city storm drain (and pool at the front of the house).
    – bob
    May 9, 2016 at 20:21
  • Landscaping contractors differs in their opinion on how to address this - first one thinks that doing outside french drain (shallow) will help moving surface water to front (this could be expensive for 75'). Second one says - just add catch basin to collect surface water and hook it up to existing downspout 4" PVC pipe - that will move surface water from swale to front. He mentioned me that water I see on surface is not a major issue but nothing would help water table rising due to rain (and moving toward natural grade) and my house will just act as dam - so basically I have to put up w/ it.
    – bob
    May 9, 2016 at 20:35
  • @bob Well, I don't suppose that increasing the grade would help with a shallow water table. The only way to deal with a shallow water table would be to raise the house higher and perhaps seal the basement like a boat. But the uncertainty is just that. I made an edit to my answer regarding how to increase the grade by adding a retaining wall to the front the house (pile soil up against the side of the wall). It should help shed water, but if the house was built too low, then, that's the problem.
    – Ben Welborn
    May 9, 2016 at 21:05
  • I see. Seems like quite expensive to achieve it - will check with contractors to price it out. In your opinion - if i leave the current situation as is and invest in power solid source (gasoline based generator) - would be be enough or will it deteriorate the foundation/footing over a time due to constant water exposure? Nothing has happen in past 16 years - but as they say it past is not an indicator of future...
    – bob
    May 9, 2016 at 21:25
  • @bob You should keep a generator above water. There are permanent and portable generators. A permanent generator is nice; they are set on a concrete pad (outside) and they are typically intended to start automatically when the power goes off. I personally just have a portable one, but the power only goes out every other year, so it's a low priority for me. Based on what you said about the water just pouring back in though, it sounds kind of futile. As for the expense, it sounds like you live in a township (sidewalk?) that might help fix the drainage issue.
    – Ben Welborn
    May 9, 2016 at 21:54

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