Is tap water and toilet water a charge?

Generally, there is no problem, but the local water quality is really bad, you can add a filter device before the toilet enters the water, as if Jiumu's toilet has its own filter device. It is enough to clean the filter often in the future. >>>More

It can't be that it's not tap water, the water used to flush toilets is generally pumped from the septic tank, which looks clear, but is actually very dirty. If there is a swimming pool in the school, it may also be water from the swimming pool, and flushing the toilet with tap water is too expensive for the school to do.

The cold water lines in the house are all one pipe.

Usually not.

Under normal circumstances, because of the presence of water pressure, the water will not flow back into the water tank, let alone into the water pipe. If the water tank inlet pipe is lower than the water level of the water tank, sometimes there is a local vacuum in the water pipe after the water is stopped, and the negative pressure generated will pump the water in the toilet tank into the water pipe, and it is best to install a check valve on the water pipe on the water tank, so that there will be no problem of water backflow in the water tank. Hope this helps. >>>More

Of course, the water at the source is the same, and it is dredged and diverted to various places through pipes.