Need Help finding LEAK on long run through woods

[CountyJohn]

My system was installed 35 years ago through my neighbors wood. Total run is 1400 feet to my house and about 900 feet through a portion of his yard and a lot of his woods. While it was very clear where it was 35 years ago --- after logging in the woods and TIME, its location is not clear at this point. The run was made with 2 inch PVC with bell ends. A shut off valve was installed at 900 feet at installation in order to isolate sections of the system. Our leak is about 1 gallon per minute., or 1400 gallons per day. We still have pressure at the house. We have isolated the leak and it is "in the woods". The shut off valve at 900 ft is 140 feet above the METER below. I contacted a leak detection service and they said it was close to the meter however after a lot of digging in the neighbors yard we found nothing-----and they came back a second time and pointed to two other places but said there wasn't any indication around the first point that they had pinpointed. (???). Finding the leak has been difficult due to the snow on the ground previously and now all the snow melt AND the rain. For three days I have shut the system down for the day and then opened the meter valve. The meter spins "90mph" for 2minutes and flows 30gallons before the meter slows to its ONE GALLON leak rate. I think 30 gallons COULD indicate that the leak is about 150-175 ft from the valve at the TOP of the hill. I have found a couple of wet spots and plan to test them today with Chlorine strips to see if it is water from the meter or just run off. I may also dig a few 18" deep holes to see if they "fill".
If we cannot find the leak -- an alternative would be to run a 1 1/4 or 1 1/2 pex through the 2 inch buried pipe along with a "tracking wire" (for future issues if there are any).
Any advice on doing a better job searching?
Any advice on finding 500 or 1000 foot rolls of large diameter pex?
Thanks for any guidance you can provide.

 

[Breplum]

many leak locating companies use sniffers after inducing specific gas, rather than sound.
I think if you have to pull new pipe, it should be a fusion weld type pipe so there will be no actual cold joints. Hire pros.
I have seen more than my share of cracked 2" PVC Schedule 40 water pipes...it was cheap but everyone got what they paid for. Sorry for your pain.

 

[Sponsor]

 

[John Gayewski]

Supply house might be able to find your some pipe. I wouldn't waste anymore money looking for the leak.