I am working in sea water pumping station project and I need to know which civil standard or specifications talk about leakages in such structures, procedures for arresting them and allowed amount of leak.
It's strictly my judgement but I try to keep leakage of seawater as close to zero as possible due to corrosion.
But if it's too late and you have to make repairs, remember, "I Cry!". International Concrete Repair Institute, ICRI.
We used to put horse manure outside of cofferdams to reduce leakage. We bought out half the stables in Santa Cruz when we built the new Dumbarton Bridge.