What is the difference in sterile water for injection and sterile water for irrigation?

Can sterile water for irrigation be substituted to reconstitute a medication?

As per pharmacopoeia guidelines Sterile water for Injection Can be used in IV, IM . which have less than 0.125 Eu/ ml endotoxin.
And Water for irrigation/ WFI can be used only injectable primary washing, disinfectant preparation, cleaning aids.
WFI is too costly, depending upon your product criticality.

You said the Sterile water for injection have less than 0.125 EU/Ml, are you sure its right answer ?

It’s as per USP <0.250 EU/ ml.
In house can be <0.125 EU/ ml to minimise the risk