Endorsements modify the policy provisions to some extent for the particular property or peril being addressed, be it scheduled property, extended or restricted coverage, etc. Most endorsements state that all other policy terms apply, so that any provisions beyond what the endorsement specifically addresses still apply. For example, an endorsement may provide increased limits for other structures because the insured has a very fancy garage and gazebo. Coverage is increased for Coverage B, but the other policy provisions concerning exclusions and perils still apply. In your case, while the endorsement does have specific exclusions, what it does not do is state that the exclusions in the endorsement replace the exclusions listed in the policy. If the endorsement said that, then it would override the water exclusion. However, the exclusions in the endorsement do not replace the policy exclusions, so those exclusions still apply.