I have my sump pump installed in the basement and the water gets discharged in the backyard.My sump pump runs 24 hrs (every 2-6 minutes interval). Discharge pipe (2" white) is connected to the 4" corrugated pipe under the ground in my backyard.The problem is when there is heavy rain the water backflows from corrugated pipe and gets collected near the foundation where it is connected to the 2" white discharge pipe . Also at the sametime I see some water collected in the middle of backyard.This does not occur when there is no rain or not very heavy rain.It means pipe is not blocked.
As a workaround I have disconnected the 4" under the ground corrugated and connected a new 2" corrugated pipe to the discharge pipe and releasing the water from that pipe.The issue comes in the winter when 2" corrugated pipe gets frozen.
Please advise.

 

Welcome to the forums.

If the water backs up the 4" pipe then it's not pitched enough or it is clogged. The 2" discharging into the 4" is ideal as the 4" won't freeze up. However, it does need to discharge in the clear. If there is a pond around the end of the 4" pipe it too will freeze shut.