A slow leak over many years can cause wet rot and decay damage to the subfloor and the toilet may start to lean to one side. If you do not have one of the new low-flow toilets, it might be a good idea to replace the older toilet or at least add a 1-gallon milk jug or tank bag to the tank to displace the stored water.
You can use paint stirring sticks, regular tapered wood shims and construction adhesive that comes in a standard caulk tube to accomplish this simple fix. The key thing to remember is to be sure the shims are about 1/2 -inch below the top of the tank lip so the tank lid doesn't touch the shims when you put it back on.
You can buy plastic toilet shims at most hardware stores. Use them under the bowl at four different points, to level the toilet and prevent it from rocking. Cut off the excess and caulk them into place. Then caulk around the entire bowl.
It might be resting on the wax ring wrong, I would try replacing it and reinstalling the toilet. You can also use a coupld of wooden shims under the low side before tightening the bolts.
There could be a broken flange. The flange is the mechanical connection where the toilet is mounted to the plumbing at the floor. There could be deterioration of the floor and an unstable base. There could be floor variations that cause the flat base of the toilet to rock on the irregular surface.
When replacing a toilet or resetting an existing toilet after a repair, it's important to set the correct toilet flange height to ensure a good seal and prevent leaks. You want to make sure the toilet sits level and does not rock on the floor, as this can compromise the seal.
The toilet tank fill tube may be damaged or incorrectly positioned, preventing the water level from reaching its proper level. Position the fill tube so water is flowing into the overflow tube (the open pipe near the center of the tank). If this doesn't fix the problem, replace the fill tube.
A toilet that is not level or centered could continue to leak water.
To move the toilet more than just a couple of inches, you will have to demolish the concrete to access and relocate water and waste lines. Then you will have to rebuild the concrete foundation and replace the sub-flooring, flooring, and fixtures.
Costs Associated with Rotating a Toilet
If you simply rotate your existing toilet yourself, you may not have to spend more than $30. This includes a new wax ring, a flange repair kit, and a longer water supply line.
Toilets are designed so that the tank sits securely on the bowl with no movement. However, if the tank is not positioned properly or has shifted over time, it may wobble or move when touched. This misalignment can happen due to improper installation or after repairs where the tank wasn't reassembled correctly.
The nuts need to be just tight enough to hold the toilet tank on, but not too tight.
However, it's the rubber O-rings that surround the bolts that are the issue. It's entirely possible to create a leak between the toilet tank and bowl if you push back against the tank too much. This is quite possible as the toilet ages and the rubber O-rings become less pliable.
The problem is usually in the fill tank. If the water level in the tank is dropping, check the flapper. If it's not sealing the flush valve opening, water from the tank will leak into the bowl, and the toilet will run constantly to keep the tank filled. Replace the flapper as needed.
To adjust the water level, pinch both ends of the metal spring clip and raise or lower the float. Slide the float down on the actuating rod and then release the spring clip to lower the water level. To raise the water level, slide the float up on the rod and release the clip.
Make sure you tighten the bolts as much as you can, as loose or damaged bolts can cause wobbly toilets. Install a new wax ring over the closet flange. Get a wax ring with a rubber flange and place it on top of the closet flange, centering it as evenly as you can.
If you loosen the bolts on either side of the base. you should be able to shim up the lower point (front or back). you can also work the side to side in this same manner if needed. Try to get everything shimmed level with the highest point of the floor and then tighten the bolts back down.
Ideally, the water level in your toilet tank should sit one to two inches below the toilet's fill valve and/or overflow tube. Some toilets even have a marker on the inside of the tank to indicate where the waterline should be.
An issue with your subfloor may require more than plastic shims or additional washers for a toilet that rocks. Still, if you have a wobbly toilet, we highly recommend removing the base and reinstalling the toilet to see whether the rocking has damaged anything under the toilet or started a leak underneath.
This type of toilet produces a greater flush as it uses gravity to flush the pan. Low/high level toilets are an ideal style to complement a traditional style bathroom.