Is your toilet leaking water from the base, here is how you can fix it!
Find the brand and model number of the toilet, if possible. This sometimes is stamped on the rim of the toilet near the tank or on the bottom side of the tank. If you can not find the number then turn off the water to the toilet at the water supply shutoff. This is usually found on the wall or floor near the toilet. If there is no localized shutoff, use the main water shutoff for the structure.
if you found the number then take your information with you to a local hardware store or plumbing supply house to purchase a replacement wax ring.
If you purchased your wax ring you can now Flush the toilet a couple of times to drain most of the water. Then, disconnect the water supply tube from the bottom of the toilet, using a large pair of adjustable pliers. Have a bucket and towels ready as some water may drain from the tank.
Then find the toilet mounting bolts on each side of the toilet base. These generally have decorative plastic or porcelain covers that can either be pulled off by hand or gently pried up with a flat screwdriver. Remove the nuts using an appropriately sized wrench or an adjustable wrench. Lift the toilet straight up off the mounting bolts and move it out of the way. You should have someone else also help you moving the toilet away because they are somewhat heavy.
Then after you have moved the toilet examine the mounting ring on the floor. You should find a yellowish wax ring about 4 inches in diameter - some brands have a plastic base that will have model information on it. Remove the ring and take it with you to purchase a replacement if you haven't already done so. Occasionally the ring will stick to the toilet base. If it does, tip the toilet over and pull the wax ring loose from the base. Do not forget to have a towels or rags by your side when you are doing this.
Then, Place the new ring on the mounting ring on the floor. Set the toilet back on the mounting ring. Seal the toilet onto the new ring. This is most easily accomplished by sitting on the toilet and very gently rocking in all directions. This will flatten and conform the wax to the base of the toilet. Replace and tighten the mounting bolts and decorative caps.
And now the last step Turn on the water and allow the toilet to fill. Flush and check for leaks.
What to do if you have a running toilet:
Remove the toilet-tank lid, Investigate the ball cock. It's a valve attached to the float (which is either a metal or plastic ball on the end of a long rod or a plastic canister that slides up and down a vertical plastic pipe). If you can see or hear water coming from this valve, it may need to be cleaned or replaced. Reach down into the bottom of the tank and press down on the edges of the tank flap (a black or red rubber cone that fits into the tank's hole). If the sound of water running into the bowl stops, you know that the flap may be deformed or worn from age and needs to be replaced.
Then, Turn off the water supply for the toilet (this valve is most often found coming out of the floor or wall near the toilet; turn the handle in a clockwise direction). Flush the toilet to drain some of the water and make the work easier. If you need to replace the diaphragm or tank flap, take it with you to a hardware store or plumbing supply house to make sure you buy the correct replacement.