A great way to support our work through a percentage of sales would be to join The Spring, our monthly giving program. Start by registering for a company account here. Once you do that, you can go into your account dashboard and settings. That's where you'll be able to upload your logo as a profile image, add a short bio, and link to your social accounts/website. You can also customize your URL.
After setting up your account, you can switch your impact to 'public' so that anyone who visits the page can follow along with your progress. Each month you can adjust your gift depending on that month's sales.
See an example of a company that donates from sales here.
Because transparency is important to us, we ask that you state to your customers the exact percent or amount (dollars and cents) that will be donated from your business to clean water.