Pet drowning and near-drowning in swimming pools is a very real problem – what many people do to prevent this, is to teach their pet how to swim in the event they find themselves in water.
For some dogs, they always find themselves in water, and you may have to wonder how to keep them out of the pool - but just as many dogs prefer to stay dry. No matter which category your pet is in, there are some important things to teach the swimming dog.
Tips on Teaching a Dog to Swim
Some dogs can naturally swim, however many dogs are born without an innate knowledge, and may have fear of the water. Training dogs to swim is not always difficult, as long as the dog is willing to learn. Dogs can even learn to swim within one or two lessons. 
The location for teaching a dog to swim must be carefully planned out. Local streams or lakes can be a start, but should not have any currents or waves, but rather should be peaceful and quiet. Allow the dog to become comfortable with the water and the area – do not rush the dog. Let them sniff the water and become familiarized.
If you are training your dog in your pool, be sure that the chemistry is balanced, and the chlorine level is not too high, around 1.0 ppm. Training your dog how to find the pool steps or pool ramp, and make an easy exit from the pool is the most important thing to teach your pet, or visiting pets, for their safety.
Encourage and help the dog to enter the pool steps, one step at a time. You can give him the incentive of treats to get him to follow you in the water, or use a floating toy.
Let your pet walk around the perimeter of the water on land to get used to things, waiting for him to be relaxed and wagging his tail before helping him in the water. do not rush your pet; if he stops - let him take his time.
If the dog is uncomfortable, he will be rigid and his head will be low and forward, possibly with his tail between his legs. If he gets in that position, you can talk gently and quietly to him, while petting and stroking him. When he starts to wag his tail again you can continue the training.
When a swimming dog starts to get into a ‘deeper’ area, where he must swim, be prepared to provide some light support, or hold the dog up if needed. You can put one hand on the base of the ribcage, or help hold the hips up, close to level with the shoulders. If you raise his rear just slightly, you can encourage a dog to kick with the hind legs, which is more effective than only swimming with the front paws (doggy paddling).
Encourage a swimming dog to extend the neck forward to keep his head parallel in the water, to improve vision. The whole time, it is important to walk alongside your dog as he moves forward, while supporting his ribcage and stomach.
Once your dog becomes a proficient swimmer, you can teach him how to dive into the water, or how to use a pool float safely!
What NOT to Do
Pushing for them to swim makes them more uncomfortable and they can feel trapped. do not just throw them into the deep end of the pool. Many dogs are not naturally born knowing how to swim, so it is important to start off slowly and make them first comfortable with the water. Do NOT shove, grab, pull or trick the dog into the water. It has to be a positive experience for him to enjoy and want to even be in the water.
Just because they are dogs, and the fact that they can learn within one or two lessons doesn’t mean you should forget safety precautions, such as using a life vest when around water. DO NOT leave a dog unattended in the water at any time. Be in the water with them, or use a leash until they are comfortable and fully proficient with the water ~and~ can swim unassisted and return to you when they are called back. 
Safe Practices – What TO Do
DO train for the safe exit. If you are on a boat or in a pool be sure to show the dog how to exit the water safely via steps or a pet safety ramp, like the Skamper Ramp, or the PetStep. Take your time to really allow yourself to demonstrate the exit area so that the dog can figure it out next time and do it themselves. Once the lesson is done give verbal praise and treats to connect treats with swimming. 
If the dog is only attempting to swim with the front feet or are not moving forward, but rather staying in one place, you can motivate them to move by the incentive of a treat. When first entering the water you can play together in a shallow area, or on the pool steps, until he gets used to the feeling of water around him.
Teaching a dog to swim is an activity worth introducing because even though many dogs may not enjoy it, it is essential to learn for safety. 
SPP Pool Pet Expert
 Chester, Jo. "How to Teach a Dog to Swim." The Daily Puppy. N.p., n.d. Web.
 "Buddy System: How to Teach Your Dog to Swim." Pet Health & Nutrition Information & Questions. N.p., n.d. Web.
 "Helping Your Dog Learn to Love to Swim." Talented Animals Blog. N.p., n.d. Web.