Let's be honest up front: no policy form is litigation-proof. Florida courts construe ambiguity against the drafter, and exclusions get read even more narrowly than coverage grants. What you can do is close the specific doors that plaintiffs' counsel walk through again and again. The case law tells us exactly where those doors are.
Causation language decides more cases than anything else
Start with Sebo v. American Home Assurance Co., 208 So. 3d 694 (Fla. 2016). Rainwater and hurricane wind (covered) combined with defective construction (excluded) to wreck a Naples home, and the insurer ended up facing a judgment north of $8 million. The Florida Supreme Court adopted the concurrent cause doctrine: when covered and excluded perils combine and can't be separated, the whole loss is covered. The detail underwriters should tattoo on their forearms is why the court got there. Other exclusions in that policy carried anti-concurrent causation language. The faulty workmanship exclusion didn't. The court treated that inconsistency as a deliberate choice and held it against the carrier.
The fix works. In Security First Insurance Co. v. Czelusniak (Fla. 3d DCA 2020), water entered through walls, windows, and doors. Walls and windows were excluded, doors weren't, and the trial court applied Sebo to cover everything. The Third DCA reversed because the exclusion carried "regardless of any other cause or event contributing concurrently or in any sequence" language, and the Florida Supreme Court declined review. Practical rule: the anti-concurrent causation preamble belongs on the entire water-related exclusion section, not on a favored subset. A form that applies it selectively invites the Sebo argument that its absence elsewhere was intentional.
If your exclusion contains a number, say what happens before that number
The standard exclusion for "constant or repeated seepage or leakage of water over a period of 14 or more days" looked airtight until Hicks v. American Integrity Insurance Co. of Florida, 241 So. 3d 925 (Fla. 5th DCA 2018). A refrigerator supply line leaked for five-plus weeks while the insured was away, eventually dumping close to 1,000 gallons a day. The carrier denied. The Fifth DCA held the exclusion was ambiguous as to damage occurring in the first 13 days, ordered partial summary judgment for the insured, and put the burden on the insurer to prove which damage came after day 13. Try allocating drywall saturation by day and you'll understand the settlement pressure that ruling creates. Whitely v. American Integrity reached the same result months later on a 30-day leak.
Compare Hoey v. State Farm Florida Insurance Co., 988 So. 2d 99 (Fla. 4th DCA 2008), where a long-vacancy toilet line leak was excluded outright. The difference between the outcomes is largely drafting precision and facts, not judicial mood. The form should make an explicit choice. Either exclude the entire loss when seepage continues beyond the period, regardless of when the seepage began or whether it was known to the insured, or affirmatively grant coverage capped at the initial period and state who bears the allocation burden. Silence on days one through thirteen is what Hicks punishes.
Definitions, endorsements, and the quiet ambiguity traps
Most water litigation in this state isn't about exotic facts. It's about a base form that says one thing and a water damage limitation endorsement that says something slightly different. Define "water damage," "seepage," and "surface water" once, then audit every endorsement against those definitions. Spell out tear-out and access costs separately, since courts routinely treat the cost of opening a slab to reach a failed pipe as distinct from the excluded water loss itself. And if you're using a limited water coverage endorsement, make the cap conspicuous on the declarations page. Buried limits draw bad faith setups, not just coverage disputes.
Before filing any revised form, hand it to someone whose job is to break it. Run the Hicks fact pattern through it. Run Sebo. If a smart plaintiff's lawyer can find two readings, a Florida court will pick the one you didn't intend. That's not cynicism. It's just the rule of the game the drafter agreed to play.