Sump pump runs, but the pit level barely changes

Visible discharge doesn’t necessarily mean the pump is keeping up: if water is still entering the pit just as fast, the level may barely drop even while the pump moves water. And little or no discharge by itself won’t tell you whether the pump is weak or the outlet is restricted. A useful distinction is whether the discharge flow looks substantial or just a trickle, while avoiding any attempt to handle the pump or pipe while it’s energized.

A practical next distinction is the accessible discharge route. With power safely isolated, look for an obvious closed valve, kink, or blockage. Any of those could restrict flow while the pump runs. If the route looks clear but discharge is still weak, that points more toward a pump or check-valve issue; I’d stop there and call a plumber rather than dismantling the assembly.

A change in the on/off pattern is useful context. Compared with its usual cycle, a much longer run while the pit level falls little can fit reduced effective removal or increased inflow. Much shorter, more frequent cycles can fit rapid inflow or a change in the float-switch range. Neither pattern identifies the cause on its own, but it helps distinguish a new change from how the pump normally behaves.

Once the pit keeps rising toward the floor, I’d stop troubleshooting and call a plumber promptly. If water is approaching electrical equipment, keep clear and don’t touch the pump or anything wet; the immediate concern is electrical exposure or water damage, not pinning down the pump fault first.