Tips to find where sump pump is discharging

Question

While investigating another question, I began to suspect that my sump pump is not discharging far enough away. There are four pipes coming to the sump pit. After a heavy rain stopped, the one from the same side as the discharge would continue to drain for a day or so into the sump pit while other pipes pretty much dried.

Is there a way I can try first before digging (which would likely require removing brick pavers)? I read about dyed water for troubleshooting septic systems. Would that be a suitable approach? Anything in particular to use?

[UPDATE] I tried pouring 10+ gallon of water with tracer dyes into the sump pit, but I cannot see anywhere outside getting wet...

Answer 1

Standard septic tracing dyes are non-toxic (important becasue you are dumping them into wherever your sump discharges) and typically fluorescent and fairly concentrated. Green and red are common. Blue seems to be less common, but available. In your case it likely does not matter, just pick a color, put it in, and go hunting - also see if it "comes back" with the late-draining pipe inflow.