Yes, I noticed that later, and thought of a better solution.
What I would do is reverse the float logic by using a resistor between +5v and the float, so that if the float contacts are open, the resistor ensures that the output is +5v.
However, if the float contacts were closed, it would take the output to 0v.
I would do it that way because, if the circuit was as it was previously, the 2 input relays would be energised all of the time, and only de-energised when the water level is high, which is not good practice (and a waste of energy).
I've not amended the circuit (as I don't know if Bart is interested or not), but well spotted @Trying_to_learn 
