Don’t use a hose. For many dogs, the hose is a scary snake-monster. Introduce water from a cup or a gentle bucket first. Hoses are for later, when they’re already in love with water.
Don’t force them into deep water. Ever. If they paddle to you, great. But if they panic, let them retreat. Forcing creates trauma that takes months to undo.
Don’t forget the towel reward. After a session, a high-value towel rub and a warm, dry spot can make the whole experience feel like a spa day. They’ll associate water with cozy, happy endings.