Submersion of connectors, not cord, is an issue. You got lucky perhaps because the standing water doesn't contact earth directly, I dunno. Last fall during a gully washer here at home, firecrackers went off big time when the 30 amp connection between my extension cord and daughter's trailer cord got overwhelmed in water. Even though it was on concrete, the slight puddle it was in was running off a few inches onto bare ground. It burned up the connectors before tripping my RV breaker in the garage.
Joel