A backyard will flood following days of soaking rain or poor drainage, but a sump pump can move that water.
But an outside submersible sump pump in a sump pit will collect debris and mud, so it should only drain water from the top of the pit, and have screening or landscape netting to strain or block leaves and dirt. Be sure the screening doesn’t interfere with the float switch.
The backyard sump pump collects the excess rainwater in one area and pumps it to a storm sewer or other area of the yard. If you think it’s from a septic source, send it to a sanitary sewer.
Dig a hole in the lowest part of the flooded yard big enough for a 5 gallon bucket. Drill holes in the top half of the bucket so the water flowing into the pit isn’t as muddy to clog the pump. Attach mud-filtering fiber or screening around the bucket, drop in the pump, attach a hose, plug into a GFI outlet and let it run.
Never allow water to pool around your foundation. Water should be sent 6 to 10 feet from the exterior of your home.
This is only a temporary pump. Once the rain stops, remove the pump, fill the hole, put the grass back and enjoy your yard.