Distributions are not taxable unless they are more than your basis in the S corporation.
A simple example of how basis is calculated
$10,000 Original Investment
$25,000 Plus/Minus: your part of the S Corp income/loss during your ownership period
($5,000) Less: your past distributions
$30,000 Basis in S Corp
Your distributions will be reported on Schedule K-1 provided by the S Corporation. You will enter it into TurboTax. Here are some additional instructions on how to enter your K-1.
The amount listed on your Schedule K, Box 1 will be taxable to you at your regular income tax rate. It is basically your part of the net income of the S-Corp.
For additional information see the below links
Tax Treatment of Distributions
S Corp Basis Calculation