Irrigation Leakage from Neighbors Yard - Any Help or Comments are greatly appreciated

[RichDavis2018]

Hello to all the builders/engineers/DIY'ers out there. After excavation, we began installing rebar. Our neighbors back yard irrigation began seeping through our dirt and has created a small pool of water in the bottom of the deep end. The rebar installation company does not wish to proceed and we have been informed this will be an issue when it comes time for inspection due to mud on the rebar/rusting rebar/etc. We have informed the neighbors who are concerned/helpful. They have turned off their irrigation temporarily to determine that is in fact what is causing the issue. Since their water has been turned off, we have seen slow improvement over the past two weeks of evaporation. We suspect their landscaper broke a pipe or forgot to cap a pipe when their piping was being re-worked for new back yard lawn. I have read that many construction companies use quicklime/hydrated lime to dry dirt and prepare the dirt for long term. My concerns are that after the shotcrete/gunnite is installed, what will the long term effects if water returns under the pool from their irrigation system once its turned back on and we are unable to inspect that area? What are anyone's thoughts on using lime to dry up the effected area? Will the lime effect the bottom of the pool shotcrete/gunnite longterm? Any help or thoughts are greatly appreciated. Truly appreciated - Rich Davis

 

[RoyR]

Wow...got to have that fixed. Amazed the neighbor has not noticed the increase in water usage.

 

[Dirk]

I've cleared puddles like that by bailing first. You'd have to do so into a 5-gal bucket and carry it out. Then a wet/dry shop vac. Sun does the finishing touches. Now's the time to trace the source of the water. If it's the neighbor's system, get it fixed until your pool stays dry for long enough of a stretch to verify the problem is solved. If it's just ground water, then your PB should know how to deal with that. Or are you owner-builder?

I've read here that sometimes a sump pump is installed permanently near a pool, to keep ground water away from the shell. That might be something to look into if the water source is on-going or untraceable.

I don't know anything about using lime. Maybe that's an acceptable solution? But my gut says not to use anything that would mask or treat the symptom, but rather find the source and solve the problem.

 

[cfherrman]

Maybe a French drain or something similar installed in that direction to keep water away from the pool.

Plaster pools do better with high water as a full pool weighs them down. A vinyl pool could float the liner. If you ever drain the pool always pretend you have a high water table and don't let the pool be empty

 

[Rich D]

Are you sure it is not ground water?
At what level is it seeping in?
If your city water has chlorine in it you can test a sample to see if it is domestic water or ground water.
If it is from the neighbors irrigation it would be in his best interest to get a pressure test done on the system and get it fixed. That kind of a leak can be costly.

As far as work continuing.. Around the NE we would put in a sump. You would dig a extra 12-18" down just outside the Excavation area, and place a vertical 6-10" dia piece of pipe (the larger the better for future use ) that would be placed into the side wall of the Excavation and go above the top of the Excavation. The bottom 18" would be perforated and stone placed around the outside. You can then place a pump in it and keep the hole dry. This is also very handy to keep a eye on the water level during construction to see if there are any additional issues.

 

[JamesW]

The bottom should be covered in rock to allow for drainage. Then, you can put a well point under the rock to remove the water or dig a dry well near the pool with a pump to keep things dry.

The dry well will give you the ability to monitor the ground water levels.

 

[RichDavis2018]

Hi Dirk, Thank you for your time and comments. We are owner-builder, but are licensed contractors ourselves, formerly general B, now just C-33 painting & decorating. A licensed concrete C-8 good acquaintance of mine warned against using hydrated lime(Calcium Oxide is generally unavailable to the public). He stated that it would produce a highly corrosive area, which may rust rebar and cause increased reactivity to the fresh shotcrete/gunite in the area which could possibly present long term issues. I would fear that if the hydrated lime was to seep through any porous areas of the shotcrete/gunite and it affected the rebar, we could see rebar rust bleeding through the plaster. We have consulted a licensed C-27 landscaper who referred us to a licensed plumber. I asked licensed plumber if he would perform a pressure test on the neighbors irrigation system. I asked if he would perform the test with air or water - he advised using water as this is a better way to test/identify issues. We intend to have the plumber perform the test. Pending the results, the neighbor may have to make repairs. Then an obvious waiting, drying, testing, retesting phase until we are sure the problem does not repeat itself. Additionally, I am considering installing a drywell with a sump pump with a water sensor as an additional long term measure underneath the pool for added insurance.

Thank you - Rich Davis

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Wow...got to have that fixed. Amazed the neighbor has not noticed the increase in water usage.

Hi Roy, thank you for the response. I did offer to compare water bills with the neighbor to identify excessive water usage per the recommendation of a PB/Designer. The neighbor seemed cooperative and inclined to compare bills, but we have not taken this step yet...great thought! Thank you!

 

[Dirk]

Good plan!

 

[RichDavis2018]

Maybe a French drain or something similar installed in that direction to keep water away from the pool.

Plaster pools do better with high water as a full pool weighs them down. A vinyl pool could float the liner. If you ever drain the pool always pretend you have a high water table and don't let the pool be empty

Thank you for your time and thoughts!

 

[RichDavis2018]

Are you sure it is not ground water?
At what level is it seeping in?
If your city water has chlorine in it you can test a sample to see if it is domestic water or ground water.
If it is from the neighbors irrigation it would be in his best interest to get a pressure test done on the system and get it fixed. That kind of a leak can be costly.

As far as work continuing.. Around the NE we would put in a sump. You would dig a extra 12-18" down just outside the Excavation area, and place a vertical 6-10" dia piece of pipe (the larger the better for future use ) that would be placed into the side wall of the Excavation and go above the top of the Excavation. The bottom 18" would be perforated and stone placed around the outside. You can then place a pump in it and keep the hole dry. This is also very handy to keep a eye on the water level during construction to see if there are any additional issues.

Hi Rich! - First of all, thank you for your thoughts. I'm not convinced its ground water. We live in the desert at 2900ft elevation. Also, it was awfully convenient that the problem occurred as the neighbor reworked all backyard irrigation and laid 1/4 acre worth of fresh sod, watering copiously since the grass went down. It appears to be seeping in from the bottom 1/3 of the deep end, but for awhile when the pool was first dug, the upper parts of the walls were also a bit moist. I am now noticing "white spots" appearing on the surface of the dirt as this problem continues on. This would confirm your thoughts on chlorine deposits coming from city water? Great idea on testing the water for chlorine...Thank you. We are taking your advice on the pressure test. We most likely are also taking your advice on installing a drywell with a water sensing sump as additional insurance. I appreciate your time. Thank you Sir!

- - - Updated - - -

The bottom should be covered in rock to allow for drainage. Then, you can put a well point under the rock to remove the water or dig a dry well near the pool with a pump to keep things dry.

The dry well will give you the ability to monitor the ground water levels.

Hi James. Thank you for responding. We've been told by multiple PB's that our area is so rocky already, adding aggregate is not required for drainage in our area. The excavator was actually only able to dig the first 3 feet, then had to jackhammer the other 5 feet of the pool just to complete excavation there was so much rock - the jackhammering nearly doubled our anticipated excavation costs$$$$. I believe we are moving forward with the drywell/water sensing sump pump as added insurance. Thank you very much for your advice, and for your time Sir!

 

[Rich D]

I believe we are moving forward with the drywell/water sensing sump pump as added insurance.

I think that is money well spent. No matter what the cause of the water you need to de-water just to keep the work progressing and if it has happened once it can certainly happen again and now is the time to add the extra insurance to protect your investment.