Consider something simpler made from just switches.
From each switch lever, suspend a float on a fixed length thread. When the water is high enough, the float releases the switch. When water is too low, the weight of the float activates the switch.
If you use two pole switches, you can organise your indicators completely independently of your pump lockout. You can get switches which are okay for mains. Or if you want to keep them completely isolated, you could use a relay.
Frm ZF Switches
simulate this circuit – Schematic created using CircuitLab
Alternatively, you could use magnets with reed relays, but I'd expect the microswitch with lever and float/weight is simplest.