Cracks are not unusual for a new construction in first year. Since its still under warranty, I think it may be a good idea to have the builder come back and inspect. They may address these issues for you.

Before you go after the sprinkler guy, step back and take a look at this from a broader perspective. Did you provide the sprinkler company with the underground piping layout before they dug? Did the builder or general contractor hire the sprinkler installer, or did you oversee this work yourself? The one who hired the sprinkler company shares the responsibility. If the sprinkler sub was given inaccurate information about the underground conditions, he is not "negligent". It is impossible to see everything underground, unless you have an accurate drawing that tells you what to look for and where. Were the other utilities marked out? Domestic water, gas, sewer, electric? Or are you in an area without any underground utilities? It is the responsibility of the competent person overseeing the excavation to check the available drawings and have an underground locator survey, if there are utilities present that are hidden. It is the property owner's responsibility to provide that information and agree to pay the cost of the underground locator survey. Both parties have a responsibility, and ignorance is not defendable. If the drawings indicate there are no underground utilities, there is no reason for a survey. The ground penetrating radar (GPR) will not detect a plastic pipe buried in soil, unless the person is specifically looking for a plastic pipe in the immediate location at a certain depth. Even then it's not very accurate. GPR is way more accurate in detecting metal pipes, live electrical, and gas lines. It will pick up the most hazardous stuff. Figure out what drawings or utility markings were provided to the sprinkler contractor, and then go from there.

Anne,I know exactly how you feel. We had our basement flood twice with sewage when an new sub division was built and hooked up to our old sewer system. I was terrified every time it rained! After a neighbour got it really bad she went down to city hall and took the mayor a gift in a mason jar! Soon after that they fixed our problem. Even now though with new sewers we still get a small wet spot on our carpet in the rec room after a heavy rain. We went down yesterday and picked up anything we could because we heard about heavy rains coming. We never did get them, yet.It has taught us to keep the basement clean though! Sure hope you are done with it and all is now well!

We had a bad flood in our basement after a big rain fall. There was over 6 inches of water and our brand new floating floor had to be removed. We still don't understand what happened. We had someone come for an inspection and said it was groundwater. However, I took this video of the sewage drain pipe when there was another bad rainfall. Why does the water seem to moving into the house? I also have attached photos of where water seems to be coming up from cracks in the basement floor? We have been here for 2 years and never had a problem with flooding. We think it might have to do the excavation when replacing the main water valve from our house to the street. Any ideas of how the sewer access pipe and ground water flooding might be related? What should we do to prevent this in the future? Is a plumber the right person to call? Thank you.