Replacing a lake water intake pipe between the cottage and lake

[Patty Bates]

Hello everyone,
I have a 4-season cottage in the Ottawa area and my water supply is lake water. The lake is about 60 feet away. I was losing prime and pressure in my system and it looks like the water pipe outside has failed. I will be replacing it completely.
I was just curious about the specifics of the job. My understanding is that a trench must be dug, below the frost line so 4 feet deep, between where the current pipe enters the cottage and the lake. Some things I'm wondering about;
- while a backhoe can do this job, should a different tool be used to dig at the shoreline and near the cottage itself?
- what type if pipe should be used? I know the current one is a flexible black pipe, 1-1/4" that looks like PVC, should I use the same material?
- before laying the pipe in the trench, should I insert some type of drainage like gravel first so that the pipe can be laid on it, or is that even necessary?
Thank you,
Patty Bates

 

[Reach4]

Losing prime would often be because the foot valve in the lake failed. A foot valve is a check valve combined with a strainer. Is there some indication that the pipe had failed?

Black polyethylene would be the most likely material for the pipe.

You would not need gravel, but you would maybe use something to avoid sharp rocks from pressing the pipe. If it is a failed pipe, then repair may be practical.

 

[Sponsor]

 

[Patty Bates]

Losing prime would often be because the foot valve in the lake failed. A foot valve is a check valve combined with a strainer. Is there some indication that the pipe had failed?

Black polyethylene would be the most likely material for the pipe.

You would not need gravel, but you would maybe use something to avoid sharp rocks from pressing the pipe. If it is a failed pipe, then repair may be practical.

Thanks Reach4! Yes I did replace the foot valve but I was still losing prime. I then took a compressor and blew air into the line, from the cottage towards the lake, and did not see any bubbles appear in the lake which tells me the air is leaving somewhere in the line, possibly a crack.

 

[Bannerman]

while a backhoe can do this job, should a different tool be used

Renting a walk behind trenching machine is an option.

https://www.compactpowerrents.com/rental-equipment/trencher/48-trencher/

Polypipe is pretty tough but sand would be a good filler to surround the pipe.

 

[Reach4]

I then took a compressor and blew air into the line, from the cottage towards the lake, and did not see any bubbles appear in the lake which tells me the air is leaving somewhere in the line, possibly a crack.

Good troubleshooting with the compressor.

I think a leak finding company could use an ultrasonic sensor to locate the escaping air.

https://terrylove.com/forums/index.php?threads/long-pex-run-underground.94536/ #5 strongly suggests a riding trencher. I don't know how you keep the path into the lake below the frost line. Narrow spade from the water, I think,

Your frost line is going to be deeper than they are talking about. If your deep dirt is clay, consider laying tarps along where the trencher will dump its dirt, so that you can put most the clay back into the trench. Discard the rest of the clay, and make the top 4 inches or better be topsoil. Do not buy "black dirt".

 

[Patty Bates]

Thanks for your suggestions. I will keep you posted on how this goes!

 

[Patty Bates]

Hi everyone! Today we had a trench dug from the cottage to the lake and a new ipex 1-1/4" pipe was hooked up to our pump. A new foot valve was installed on the other end of the ipex pipe and placed into the lake about 4 feet below the water line. After priming the system, water was restored to the home!
My pump seems to be acting a little odd though.
Before we had to perform this repair: when the pressure on the pump dropped below 40 PSI, the pump would run for about 5-10 seconds and bring the pressure up to 60 PSI. All good.
After the repair: when the pressure on the pump drops below 40 PSI, the pump seems to "struggle" and runs for about 20-30 seconds to bring the pressure up to 60 PSI. As soon as the pump shuts off, the pressure immediately drops to 52 PSI and turns off again until the pressure goes down to 40 PSI.
Any thoughts? I was told that it may take a bit of time, a few days, for the system to adjust a little bit, maybe there is a bit of air in the home's piping going to sinks?
Thanks! Joel

 

[Reach4]

Slather all accessible joints on the suction line, including the connection at the pump, with shaving foam. Run the pump. Look for shaving foam getting sucked in.

On the other hand, if there is some air trapped, maybe dump water, at a high rate, into the yard or lake for an hour or so continuously.

One more thing: did you change the plumbing between the pressure tank and pressure switch?

Yet one more question: Is the lake level in February lower or higher than now? If lower, you might take that into account for placing the intake.

 

[Patty Bates]

Thank you Reach4, I will try the method you described with shaving cream to see if anything is being sucked into the system.
I will also try to dump water from an outside hose for an hour to see if there is any air trapped that might be clogged in the system.
I did not change the plumbing between the pressure tank and the pressure switch.
The lake level in February is about the same, plus my water line is tied off to my dock which stays in the lake year round.

 

[Patty Bates]

I also provided a short movie clip which shows the pump running. See the pressure gauge and how it quickly drops down as the pump shuts off. The pressure then stays at that level.

 

[Bannerman]

Patty Bates, have you considered replacing the exsisting pump with a submersible placed directly in the lake?

A submersible would eliminate priming and air leak issues as the water would be supplied under positive pressure the entire distance to the cottage. One drawback would be running electrical power to the pump if you have already backfilled the trench.