f you’ve ever looked at photos of Venice with people walking on raised walkways or wearing rubber boots, you’ve seen Acqua Alta—literally, “high water.”
But what exactly is Acqua Alta?
Does it mean Venice is sinking?
Is it dangerous for travelers?
When does it happen, and how can you avoid it—or even experience it safely?
In this definitive guide, we’ll break down everything you need to know about Acqua Alta: from the science behind the tides to the real-life experience of walking through water in Piazza San Marco. We’ll also share practical tips, local insights, and what Venice is doing to protect itself with projects like MOSE.
📚 Table of Contents
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What Is Acqua Alta?
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The History Behind Venice’s High Water
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When Does Acqua Alta Happen?
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Where Does Acqua Alta Happen in Venice?
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Why Does Acqua Alta Occur?
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How High Does the Water Get?
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Is Acqua Alta Dangerous?
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What’s It Like Visiting During Acqua Alta?
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How Venetians Live With It
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What Is MOSE? And Is It Working?
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How to Prepare for Acqua Alta as a Tourist
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What to Wear and Pack During Acqua Alta
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Apps and Tools for Monitoring the Tides
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Acqua Alta & Climate Change: The Bigger Picture
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FAQs About Acqua Alta
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Final Thoughts: Should You Worry About Acqua Alta?
1. What Is Acqua Alta?
Acqua Alta means “high water” in Italian. It refers to the temporary tidal flooding of low-lying areas in Venice, usually caused by a combination of high tides, strong winds, and atmospheric pressure changes.
This flooding usually lasts a few hours, submerging parts of the city, especially Piazza San Marco, before the water recedes. It’s not a permanent condition—Venice does not live underwater—but a cyclical event that happens mainly in the fall and winter.
2. The History Behind Venice’s High Water
Venice has always lived in a delicate balance between land and sea. Built on wooden piles over a shallow lagoon, the city was once protected naturally by marshes and tides. But over time, human development, rising sea levels, and subsidence (the ground sinking) changed that balance.
The first recorded instance of Acqua Alta dates back to the 13th century, but it became more regular in the 20th century. The exceptional flood of 1966, when waters rose over 190 cm above sea level, damaged much of the city and triggered calls for long-term solutions.
3. When Does Acqua Alta Happen?
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Acqua Alta typically happens between:
🗓️ Late October and early March,
especially in November and December.
These are the months when:
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Tides are naturally higher due to the alignment of the sun and moon
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Winds from the Adriatic Sea (scirocco) push water into the lagoon
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Rainfall and atmospheric pressure contribute
Most common hours:
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Early morning (4:00–6:00 AM)
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Late evening (9:00–11:00 PM)
💡 Tides usually come in and recede within 2–4 hours.
4. Where Does Acqua Alta Happen in Venice?
Not all of Venice floods equally.
Most Flood-Prone Areas:
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Piazza San Marco – always the first to flood
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Rialto Market
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Fondamenta Nove (north side of Cannaregio)
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Campo Santa Margherita
Less Affected Areas:
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Dorsoduro – one of the highest points in the city
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Zattere promenade
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Castello’s eastern side
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Giudecca island
📍 Tip: Ask your hotel for flood-prone zones near you.
5. Why Does Acqua Alta Occur?
It’s a mix of several natural and manmade factors:
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Astronomical tides – Especially spring and autumn equinoxes
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Atmospheric pressure – Low pressure lifts sea levels
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Winds – The scirocco pushes water into the lagoon
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Rainfall – Contributes to local water levels
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Subsidence – Venice’s ground level has sunk 23 cm in 100 years
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Sea level rise – Climate change is adding a long-term threat
6. How High Does the Water Get?
Acqua Alta is measured in centimeters above sea level, with official measurements taken at Punta della Salute.
| Level | cm above sea | Impact |
|---|---|---|
| 80 cm | Light | Wet sidewalks, minor puddles |
| 100 cm | Moderate | Flooding in low zones |
| 120 cm | Serious | Raised walkways used |
| 140+ cm | Exceptional | Most of central Venice affected |
⚠️ The record high was 194 cm on Nov 12, 2019—caused massive damage.
7. Is Acqua Alta Dangerous?
Generally, no—Acqua Alta is inconvenient but not dangerous.
There’s no “tsunami” or sudden wall of water. It rises slowly, giving locals and tourists time to adapt. You may get wet shoes or need to reroute your walking, but you won’t get swept away.
Exceptions:
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⚡ Don’t wade through water near electrical outlets
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🚫 Don’t try to swim in it—it’s not clean
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⚠️ Avoid rushing around flooded steps or bridges
8. What’s It Like Visiting During Acqua Alta?
Imagine Venice with water lapping over marble steps, locals rolling up their pants, and elevated wooden walkways (passerelle) popping up around the city.
It can be frustrating or magical, depending on your attitude.
You might:
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Be rerouted by flooded alleys
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Wear waterproof boots or plastic over-shoes
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See Piazza San Marco reflect the sky like a mirror
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Hear sirens alerting tide levels (listen for 1 to 4 tones)
📷 Photography tip: Get up early—acqua alta makes for unforgettable photos!
9. How Venetians Live With It
Locals treat Acqua Alta like bad weather, not a disaster.
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Schools may delay or close for a few hours
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Shop owners put up aluminum flood barriers
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Boots are kept at the office or school
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Kids love jumping puddles in waterproof suits
It’s a nuisance—but also part of Venice’s identity.
10. What Is MOSE? And Is It Working?
MOSE (Modulo Sperimentale Elettromeccanico) is a massive flood barrier system designed to protect Venice from extreme tides.
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Built over 20 years at a cost of over €6 billion
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Consists of 78 mobile gates that rise from the sea floor at the lagoon’s three inlets
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Fully activated since 2021
✅ MOSE successfully blocked record tides in October 2020 and has been used multiple times since.
💡 It is not used for minor Acqua Alta (under 110–120 cm) due to cost and environmental balance.
11. How to Prepare for Acqua Alta as a Tourist
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Check tide forecasts (see next section)
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Pack waterproof shoes or boots
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Bring an extra pair of socks & flip-flops
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Ask your hotel if they provide rubber boots (many do!)
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Avoid accommodations in low areas like San Marco
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Embrace flexibility—rearrange your route if needed
12. What to Wear and Pack
👢 Waterproof boots or buy disposable overboots (€5–€10)
🧦 Quick-dry socks
🩳 Rollable pants or water-resistant clothing
🎒 Water-resistant backpack or bag cover
📱 Offline maps in case phone signal drops
13. Best Apps and Tools to Track the Tides
Use these tools for accurate updates:
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Hi!Tide Venice app (iOS/Android) – Real-time water levels
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Centro Maree Venezia – Official city tide service
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Telegram channel @acquaaltavenezia – Real-time alerts
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City sirens (1 to 4 tones = severity)
🌀 1 beep = 110 cm
🌀 2 beeps = 120 cm
🌀 3 beeps = 130 cm
🌀 4 beeps = over 140 cm
14. Acqua Alta & Climate Change
Venice is at the front line of climate change. Acqua Alta is not just a local inconvenience—it’s a global warning sign.
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The frequency of extreme flooding events has increased
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Sea level rise projections show parts of Venice could be under water permanently by 2100
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MOSE is a temporary solution, not a permanent fix
Venice’s survival depends on global action as much as local barriers.
15. FAQs About Acqua Alta
❓Can you still visit Venice during Acqua Alta?
Yes! Most of the time, it’s manageable and adds character to your visit.
❓Can Acqua Alta ruin your trip?
Only if you’re unprepared. Flexible shoes and mindset = fine.
❓Do gondolas still run?
Yes, though some stops may pause temporarily.
❓Should I cancel my trip if the forecast shows flooding?
Not unless a record tide is expected. Most days it’s minor and over in a few hours.
16. Final Thoughts: Should You Be Afraid of Acqua Alta?
No. You should be informed, not afraid.
Acqua Alta is part of what makes Venice… Venice.
It’s a reminder that this city lives on the edge, suspended between water and wonder.
If you visit during Acqua Alta, embrace it. Take photos of the reflections. Walk the passerelle. Laugh with the locals in rubber boots. Just don’t forget to dry your socks later.
🎒 Want a guided tour of Venice—even during Acqua Alta?
At Tour Leader Venice, we offer rain-or-shine private tours with licensed guides who know how to navigate the tides, avoid flooded streets, and still show you the magic of the city. Local, stress-free, and unforgettable.
