Before you can begin repairs, it’s important to have a basic understanding of how your toilet tank works.
How the Toilet Tank Works
The toilet tank’s function is to hold a quantity of water until you flush the toilet, at which time the water in the tank rushes down through an opening in the bottom of the tank and into the bowl, forcing waste out of the bowl and into the home’s drain and sewer lines. There are two major toilet parts in the tank that make this possible: the flush valve and the fill valve. The toilet fill valve is the mechanism that fills the tank with water. It is also known as a “ballcock” or a “refill valve.” The fill valve is usually located to the left side of the tank as you look down from above with the tank lid removed. Fill valves comes in four basic variations:
Plunger-type ballcock: the oldest type, usually made of brassDiaphragm-type ballcock: older styles may be brass, newer types are plasticFloat cup fill valve: a newer design, usually made of plasticFloatless fill valve: another newer design; not allowed by some codes
Whatever the design, the fill valve works to automatically open the water supply valve when the water level falls in the tank during a flush, then shuts off automatically when the water level rises to a specific level in the tank. Depending type of design, the valve is operated either by a floating ball or a float cup that moves up and down with the water level in the tank. Floatless fill valves operate by sensing water pressure at the bottom of the tank. If you remove the tank lid and watch what happens inside the tank during the flush cycle, you will quickly understand the mechanics of how a toilet flushes. Although the term ballcock is sometimes used to refer to any type of fill valve, technically the term applies only to two types—the plunger-type and the diaphragm-type—both of which have the identifying float ball that operates the valve via a long arm attached to the ball. Although they are rarely used in new toilets, you may run into both the plunger-type and diaphragm-type ballcocks in older toilets. The mechanism is very simple, and where adjustments to the water level are needed, it is done by bending the float arm up or down to change the point at which the float ball shuts off the water supply. For example, when a toilet continues to run after the flush cycle is completed, it is usually because the water level is too high in the tank. By bending the float arm downward, the float ball will shut off the water at a lower tank level. Adjusting the water level in the tank is a matter of “fine-tuning” the point at which the float ball shuts off the valve. Ballcock valves are prone to problems, so if you have one of these, it is a good idea to replace it with a more modern float-cup style fill valve. Replacement is an easy DIY project. Integrated into the flush valve is a vertical overflow tube that extends up into the tank from the base of the flush valve. The role of the overflow tube is both to prevent water from overflowing the tank, and also to allow a small amount of water to flow down into the toilet bowl as the tank is refilling. A small refill tube placed into the top of the overflow tube allows a small stream of water to flow down into the bowl during the refill cycle. This restores the level of standing water in the toilet bowl, keeping the trap sealed. Fixing a running toilet is relatively easy to do. The problem occurs either because the flapper is not seating itself correctly in the opening of the flush valve, or because the water level in the tank is too high and allows water to flow over the top of the overflow tube and down into the tank. With either problem, the repairs are very easy to make. All refill valves have methods for adjusting the water level, and flapper valves are easy to adjust or replace.
Reconnect the lift wire or lift chain that connects the lift arm from the flapper. Adjust the handle mounting nut inside the tank; it has reverse threads that require counterclockwise rotation to tighten.
While a little condensation is normal in the summer months, an actual puddle of water at the base of your toilet indicates a real problem. There is a great chance this water is dirty, so to keep the problem from worsening, it’s best to avoid using your toilet until it’s fixed. Normally this problem is caused because of problems with the wax ring that seals the base of the toilet (the horn) to the drain opening set into the floor. You’ll have to remove the toilet in order to replace the wax ring. Although this might seem like a major project, it’s actually not all that hard. You can save a lot of money by doing the work yourself rather than calling the plumber.
