First some background, and then a question:
I recently had a sump line fixed outside of the house. There was a broken PVC pipe under the patio, which was repaired. When they broke open a small area of the patio to look for the line, there was a wide open area under the remaining cement from where the water had washed everything away. This must have been going on for some time. The water had been cycling back into the sump continuously because the water was right next to the house.
After they fixed the line, we checked, and it appeared the sump water is going into a storm drain. They put paver sand (I think that's what it's called) in the area they opened up. After checking this, I realized they hadn't filled in the empty area, so we pushed sand back there. They went back to the store and picked up play sand (not paver sand), filled in the rest of the area, and put concrete over the top. It's ugly, but it slopes away from the house. When it rains, we still get some water sucking into the concrete under a door jam that leads out to that patio. (It appears that entire section of concrete was pushed up when water underneath it froze during the winter, but it's hard for me to tell).
Another section of the patio dips very slightly towards this new cement fill in, and when it rains there's a wet area that one or two swipes of a broom removes.
We've gotten rain since then, and had zero water go into the sump from what I can tell.
Here's the question:
We've had rain off and on for a couple of days. Last night it was especially intense, and we finally started getting water into the sump. The sump was running about once a minute from what I could estimate last night, and right now it's running about every two minutes.
I went out to the yard, and I hear the water from the sump immediately followed by what sounds like a sucking noise. It's definitely out in the yard, and away from the foundation about 15 to 18 feet. I'm pretty sure it's the sump, because it times out about the same amount of time as the pump.
Is this normal? I was surprised the line didn't go into the sewer, and now I'm worried about the sump.
Any thoughts or ideas?
It is illegal to tie a sump pump into a sewer in almost every town. You can tie them into storm drains, but thats not all that common. Often times the sump pump is tied into a dry well (basically a large hole in the ground filled with rock that will allow the water to drain naturally back into the soil away from the house). Maybe this is what your setup is like.
Your sump pump probably has a backflow preventer and so long as it does the water the pump pushes out shouldn't be going back through the pipe and into the sump pit. You should verify this. If this checks out maybe you should do a little exploratory digging and see what the noise is. It could be just the last of the water draining out of the pipe and nothing to worry about.