How long can iPhone 7 be in water

Your iPhone can be immersed for as little or as long as you want, so long as you are also willing to purchase a replacement at full price and not expecting anybody else to pay for any adverse results arising from the dunked iPhone. Same answer for sticking an iPhone into a blender and asking yourself “will it blend?”, or any of the many other device-longevity-averse activities possible.

IP ratings are under laboratory conditions with a new iPhone and with pure water.

A depth rating of 50 meters is generally considered the minimal level for surface swimming with a device. No diving. 100 meters for deeper snorkeling, some water sports. 200 meters, deeper snorkeling and surface diving and more serious water sports.

https://en.wikipedia.org/wiki/Diving_watch#Water_resistance_classification

IP68 (at pressures less than 50 or 100 meters) is best considered to be rain resistant. Not resistant to dunking. Not unless you plan to replace the device immediately due to failure, or to replace it later due to materials degradation or corrosion arising from impurities in the water.

Official details for a device that Apple does warrant (some) dunking > About Apple Watch water resistance - Apple Support

The photo used above is seen elsewhere, too, and the info and captions are quite clear:

If you really need to use an iPhone near or in water, get a sufficiently-depth-rated case for it, and use the case.

You are VERY lucky.

Here’s an explanation of what water resistance means→Understanding Water Resistance - Apple Community

Here’s what Apple says about it:

iPhone 7, iPhone 7 Plus, iPhone 8, iPhone 8 Plus, iPhone X, iPhone XS, iPhone XS Max, iPhone XR, iPhone SE (2nd generation), iPhone 11 Pro, iPhone 11 Pro Max, iPhone 11, iPhone 12 Pro, iPhone 12 Pro Max, iPhone 12, and iPhone 12 mini are splash, water, and dust resistant and were tested under controlled laboratory conditions; iPhone 12 Pro, iPhone 12 Pro Max, iPhone 12, and iPhone 12 mini have a rating of IP68 under IEC standard 60529 (maximum depth of 6 meters up to 30 minutes); iPhone 11 Pro and iPhone 11 Pro Max have a rating of IP68 under IEC standard 60529 (maximum depth of 4 meters up to 30 minutes); iPhone XS, iPhone XS Max, and iPhone 11 have a rating of IP68 under IEC standard 60529 (maximum depth of 2 meters up to 30 minutes); and iPhone 7, iPhone 7 Plus, iPhone 8, iPhone 8 Plus, iPhone X, iPhone XR, and iPhone SE (2nd generation) have a rating of IP67 under IEC standard 60529 (maximum depth of 1 meter up to 30 minutes). Splash, water, and dust resistance are not permanent conditions and resistance might decrease as a result of normal wear. Do not attempt to charge a wet iPhone; refer to the user guide for cleaning and drying instructions. Liquid damage not covered under warranty.

0 hours, 0 minutes, 0 seconds.

fardeen306 wrote:

No I you are wrong my iPhone 7 survived water test

Then you and your iPhone are very, very fortunate.