Is surface drainage through the crawl space of a house a bad thing?

Asked by Bill Hays, Cardiff, AL Wed Jan 25, 2012

I am listing a home in San Diego in which rainwater from the next door neighbor runs through my clients property via the crawl space and comes out on the other side of the home and is sump pumped to the street. I found that this was a major red flag and felt we should consider looking at ways to fix the drainage prior to listing the property.

The seller, who is originally from the midwest (where basements and sump pumps are common, seems to think the situation isn't unusual (Pt. Loma) and this condition is how he purchased the property. The downstream neighbor has actually installed drainage pipes beneath his house to deal with the situation. So do I press for further professional evaluation or just go along with the "this is normal" approach.

I would think a home inspection would call this out. I would expect the buyer to say, "As is." The problem in my mind is that this potentially becomes a lawsuit down the road, even if it is disclosed. Any thoughts?

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John Arendsen, Agent, Leucadia, CA
Thu Jan 26, 2012
Hello BeachBroker and fellow Encinitas neighbor. I have to applaud and give a thumbs up to Steve on his remark: I think the only time it is appropriate to have water running under your home is when you live on a Yacht!
Albeit very humorous it is very true and a very important issue.

As a general contractor distressed property rehab specialist for the past 3 decades we've done hundreds of drainage projects all over the SoCal area. Additionally I've been a "cross lot drainage "Expert Witness" on dozens of drainage issues and am currently involved with a multi million dollar class action litigation on this very subject.

I can tell you first hand that water in, around or under a dwelling is trouble and a one way ticket to a very costly law suit let alone repair bill. By law your neighbor is not allowed to let water drain from his lot to any adjoining private or public property.

Drainage be it surface runoff or subsurface percolation should always be caught and diverted to a storm drain system; usually the street gutter, whereby it will flow to the major storm drain system. This sometimes if not always requires a two fold approach.

The first is to install a French drain system around the entire perimeter of the structure. A French drain is a subterrainean drain comprised of trenching, installing a gravel envelope around a filter cloth thereby allowing water to filter through it and into a perforated drain pipe installed on at least a 1% slope, aka fall line) which leads to the storm drain system or a sump well and pump system.

The second type of drain (usually run in the same trench as the French drain if not tied into it) is a surface drain system whereby a soils and/or civil engineer locate the low spots and install a catch basin with drain pipe leading to the trench and escorting the water to the storm drain system or to the sump well where it is pumped into the main storm drain system which is usually the street gutter.

I must also give Cory a thumbs up for her astute observation regarding potential structural ramifications to the home. It's not uncommon, especially in San Diego's predominantly very expansive clay soil environment to realize mild to severe movement as the clay expands and contracts over the years.

This perpetual motion causes a structure to settle and shift resulting in cracked founations, seepage to the interior of the structure if it's a slab on grade or into the crawl space where it sits and collects for years on end resulting in mold issues as was addressed by Frank.

All in all it is definitely not normal nor is it acceptable and should be addressed and corrected ASAP. Given home is in San Diego and we are still actively involved in this trade skill I would be more than happy to have my son, Chad Arendsen, principal of "Chad of All Trades" give you an assessment and cost to repair this problem for either your seller or buyer.

However, be advised that a properly designed and installed drain system is still not a cure all to the problem. A drainage issue is a drainage issue because water inherently seeks its lowest level and unfortunately that can end up at the doorstep of someone's home.

The only remedy is to catch and divert the water but it's still going to be an ongoing issue which will have to be periodically monitored and maintained as the drain pipe can clog up with soil and roots and the sump pump system, if needed, needs to be periodically inspected and maintained.

Should you have any other questions or concerns please feel free to contact me at 760 815-6977, or log onto our website at Good luck.
1 vote
Michael Fran…, Agent, Borrego Springs, CA
Thu Jan 26, 2012
Disclose, disclose, disclose. If he owner is not worried to disclose it then you shouldn't. My guess is your not the expert and don't have to be.
Good Luck
2 votes
Frank Dolski, Agent, Lahaska, PA
Thu Jan 26, 2012
Anytime that there is surface water involved there is a chance for mold and other problems. I have seen an open spring in an old home but never what you mentioned. Can it be remediated?
2 votes
Jennifer Bla…, Agent, Basking Ridge, NJ
Thu Jan 26, 2012
It doesn't sound right to me - but if the seller is digging in, you have done your part by "warning" him it might be an issue. Disclose it - if it's an issue it will impede the sale - let the potential buyers show your seller that it needs to be done (and I don't mean during inspection when the issue is uncovered, I mean when you get no offers because it's a problem....)
2 votes
Alex Gomez, , San Diego, CA
Thu Jan 26, 2012
In my opinion, fix it and sell it. Make sure the work is done professionally so it won't afect the marketability of the property. Good work will include guarantees and certificates; this way there will be someone accountable, and reduce liability. If you go "as-is" you will limit potential FHA and VA buyers, you will have to sell at a reduced price, and more prone to the "litigious state of California"- lawsuit. However, if the repairs don't make business sense then sell "as-is" but with some thurough disclosures. Good luck. AG
2 votes
Steven Ornel…, Agent, Fremont, CA
Wed Jan 25, 2012

I think the only time it is appropriate to have water running under your home is when you live on a Yacht!

From what you describe it sounds like a French drain AROUND the perimeter of the home connected to the sump pump would be a better call. I would definitely get the opinion of a local drainage specialist and then remedy the issue to mitigate post transactional exposure.

"The seller, who is originally from the Midwest (where basements and sump pumps are common, seems to think the situation isn't unusual..."

It really doesn’t matter what the Seller thinks, we're not in the Midwest anymore; we're in the litigious State of California. Remedy the issue and then place it on market with full confidence there’s nothing that will come back to bite the parties involved.

2 votes
BXT AXT, Agent, San Diego, CA
Wed Jan 25, 2012
Here in San Diego when you get mud under a wood structure you will eventually get subterranean termites. Since the seller has not a problem with it the simple solution would be to go "As is".
2 votes
Shannon Ande…, Agent, San Diego, CA
Wed Jan 25, 2012
When in doubt........Disclose, Disclose, Disclose. As long as it is disclosed and the buyer has opportunity to investigate, it seems to me thats all that can be done. DO NOT sugar coat the disclosure and make it seem like it is no big deal or "normal" either. Be very frank about the issue. Is there standing water under the house? Are there foundation issues? Any issues should show in an inspection and can be addressed at that point. If it is an issue, the buyer will be alerted to it if it is something more than you have disclosed. So short of the seller paying for expensive engineering reports or getting a plumber out there, disclosing seems to me to be the way to go.
2 votes
Bill Hays, Agent, Cardiff, AL
Wed Jan 25, 2012
Thanks Cory. Also with moisture comes another unmentionable "M" word that is a real health concern wildcard. The east side of his house stays damp all winter long. I typically recommend home inspections prior to listing so there are no surprises and think your perspective is right on.
2 votes
Cory La Scala, Agent, San Diego, CA
Wed Jan 25, 2012
I would definitely get another opinion on this. My thinking is that if water regularly runs over soil, it could possibly cause it to eventually shift (some will seep in, right?) and that won't be good for the home structually.
Even if it's not a problem and is normal, wouldn't your seller want to know for sure? Sol in some parts of San Diego can be poor to begin with. Foundations, framing, windows ... all expensive to fix. You could get an an inspector with extra foundation and soil training to offer an opinion. It could save the seller from a potential, and really costly I'd think, lawsuit from the buyer if something happens. And, your seller will have to disclose it, so better to have been proactive and put the buyer's mind at rest with the inspection report. If you have buyers cancel because of it, the listing will sit on the market longer and down goes the price. Just my opinion. Good luck with this!
2 votes
John Arendsen, Agent, Leucadia, CA
Fri Jan 27, 2012

A rain gutter sysem around the roof line is as natural as grandma and apple pie. However, do be careful tying it into another drainage system. It's important to make sure that the other drain systems main drain pipe is larger than all the other drain pipe leading to it.

Example if you're running a typical 3 inch perforated French drain pipe and a 3 inch tightline (solid pipe) to transport the surface drainage and still another 2x3 inch down spout all into one main drain line be sure to make that main drain line at least six inches in diameter. Faliure to do this will result in a back up of all the drainlines which will totally defeat the purpose and will exacerbate your problem.

If the property has enough fall to gravity flow the water to the street gutter you would then need to install a manifold that would resevoir the water and transfer it to a series ot smaller (generally 2 to 3 three inch pipe) tight line in order to be able to core cut through the curb.

If the lot does not have enough fall to the street gutter then you will need to install a sump well and pump system at which time whence you could then pump the water to the street gutter with a 2 inch tight line. Should you need a sump system it will also be necessary to install a dedicated 110v outdoor reciptical. In many if not most cases you would also need to consider a back up system in the event of a primary pump failure. Hope this helps

In any event from the sound of things you may want to consider retaining a soils engineer in order to determine the depth of the saturation in order to deal with the percolation issue which is the ground water that is forced up through hydrostatic pressure. This is just as important as catching and diverting the surface runoff. Good luck.

760 815-6977
1 vote
Bill Hays, Agent, Cardiff, AL
Thu Jan 26, 2012
John et al - thanks for your perspectives. I found myself thinking the same things as I have a background in construction myself. This seller is a long time friend and has lived with the problem for almost 6 years. I have asked for a copy of his home inspection from 2006 and feel his agent at the time really missed this issue.

The other fix I have suggested is a rain gutter system for his roof which can be plumbed directly into a drainage system as another method to keep water away from the house. I will be looking to see if the neighbor has gutters and if not, see if we can get them to install them as well. He is having another agent (vanity name in the area who claims to be the local expert) come over tomorrow (actually at my suggestion). Many agents look past these issues to get the listing and then deal with them as they are brought forward by buyers. He is smart and will stick with me, but it will be interesting to hear what she has to say.

Thanks again everybody!
1 vote
Jim McCowan, Agent, Arlington, VA
Thu Jan 26, 2012
I'd have a structural engineer come in and also check the local building codes. Water flowing under a house at the surface level can't be good!
1 vote
HousesToHom…, Agent, San Diego, CA
Fri Jun 13, 2014
I would get a home imspector ASAP. Real estate agents really should not answer a question like this as we are not trained in these areas. However they can give you a list of a trusted inspector, this could save you a lot of money in the long run. Best of luck.
0 votes
karablader, Home Buyer, Utah County, UT
Thu Jun 12, 2014
I lived in the Midwest for almost 15 years and although basements and sump pumps are common, having water run underneath your house is not. That could cause a variety of problems in the future. I wouldn't go with the "this is normal" approach. This should be checked out and dealt with now.
0 votes
I agree that water running under your house is something to be concerned about. Even if the seller bought it like that and has been living with it for 15 years, there can be mold and foundation problems. There are lots of ways to fix the problem though, as mentioned by John. There are lots of different drainage systems you can have installed and then sell the house. Otherwise, definitely disclose the issue!
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