Can someone please identify the purpose of this covered plastic pipe in my front yard. I can provide further details as necessary. I thought it was a drain clean-out, but the plumber disagreed. In the back yard, there is a clean-out for the combined sewer/storm line. Photos attached with cap on/off.
The cap is called a "popup emitter" and is used to cap a drain line. When there is water pressure the center part "pops" up and allows the water to flow.
Perhaps it's from a downspout or a sump pump. It looks as though it may be clogged up.