https://www.yourhikeguide.com/buckskin-gulch/

Buckskin Gulch. The longest slot canyon in the world. Backpacker Magazine named it the most dangerous hike in the United States. Makes you want to hike it tomorrow, right?! This is a hike only for those that are well-prepared. A flash flood while in Buckskin Gulch is deadly. Flash floods up to 100 feet high rip through Buckskin Gulch, as evidenced by full-sized logs wedged dozens of feet over your head. With the walls hundreds of feet above, there is little or no escape from a flash flood. Make sure that there is no rain in the forecast. Storms as far away as Bryce Canyon can bring a wall of water into Buckskin Gulch. Be sure to carry plenty of water for your entire hike, as water in the gulch is not clean nor reliable until late in the hike. All of this aside, Buckskin Gulch is an amazing hike, and will test your endurance while rewarding you with an experience that you will always remember!

Wirepass to White House
Distance – 20.6 miles roundtrip, and a car is needed at each trailhead
This hike through Buckskin Gulch and up the Paria River is 20.6 miles in length, and can require wading through several stagnant pools or none at all, it just depends on your luck. 

^ that mileage seems way off

As long as you maintain a comfortable walking pace during the hike through Buckskin, you should be able to finish the hike in about 12-13 hours. We were able to finish in 9 hours and 45 minutes, which included just a couple of ten minute breaks.

infamous “Cesspool” which was about 35 feet long and just under knee-deep. It smells… putrid. Yes, putrid is a great way to describe it. This “Cesspool” on very rare occasions is bone dry. Other occasions, hikers wade in neck-deep stagnant water for 150 feet. Be prepared for wading. It is typically between knee and waist deep, and is similar to the consistency of chocolate syrup. I would recommend wearing or bringing along water shoes, because walking with wet socks and sneakers for 20.6 miles can be miserable. The cesspool is about 7.5 miles from the Wire Pass Trailhead. About one half mile past the cesspool, the canyon walls lower to about 100 feet, and on the left side of the canyon you may spot the Middle Route exit, which is a Class 3 scramble to the canyon rim. Some backpackers exit the canyon here to set up camp and spend the night, but if you’re planning on completing the hike in one day, just keep on going. 

Nearly four miles after the Middle Route exit, you’ll arrive at the only big obstacle in Buckskin Gulch, a 15-18 foot dryfall that you can descend with the aid of a rope and moki steps chipped into the rock, or you can climb down it with two logs wedged together. It’s not too difficult to navigate, just take your time. I brought my own rope just in case, but there was a rope waiting there for us to use. It’s about another 1.5 miles to the confluence of Buckskin Gulch and the Paria River. Water will seep from the canyon walls, and will collect on the canyon floor in a shallow, clear stream and run down to the confluence.