There are other skills plumbers need aside from being able to work with water. One of the most common things that a clog on is fixing water lines.
When you get to the house stand if front of the toilet and locate the water shut off valve. Should be down below the toilet on the wall. Just turn it off (righty-tighty) completely and flush the toilet. All the water should have left the tank, well at least most of it. If there is remaining water line repair get it out with paper towels or a rag. The important thing is that no more water came in. If it did then your valve is not shut all the way or not working and you need additional help.
One other common design that is considered "washerless" was made famous by Delta and copied by several other makers. It uses little "cup" seals that fit over springs recessed in the back of the valve body. The springs press these "seals" against the cartridge and regulate the flow through little tapered openings in the cartridge. If you have one of these and it's dripping, changing these springs and seals will usually correct it. Here's a tip. Once you have the cartridge out of the way, insert a phillips screwdriver into the seal and pop both the seal and spring out. Stick the new ones on the end of the screwdriver to help guide them into place. This is especially helpful if you don't have long slender fingers.
Once you have disconnected the tank remove it from your work space. Do a thorough measurement of the remaining pipe for reference when you go to the hardware store. I will be honest with you, you might need to make a few trips back to the store. Once you get the new tank, slide it into place to line up the plumbing.
OQuality water line repair referrals from friends family or acquaintances can be an invaluable cog in the process. By getting referrals from people you trust, you can make your search a much faster process.
68. Sea sickness: I always keep a bucket in the cockpit, much better that the sufferer is sick into a receptacle of sorts than tries to be sick over the side.
The plumber you hire does not normally do heating but will do hot water heating or in floor heating in the house. Some places you can use the water heater for both domestic hot water and for in floor heating if the heating is a secondary heat. Check with your local plumbing codes on this to be clear.