Problems with toilet pressure are common but this does not mean that they are normal. In most cases we are dealing with problems in the case of 2 toilets on a flush line. One will flush but with a low pressure. You will basically only notice it trickling and this means you end up needing to flush more than once and water is wasted. In some circumstances you will notice that using some cleaning products will aid but this is not something that happens very often.
The problem is most people think that pressure is linked to draining. This is not true! Pressure only helps in filling up the tank and the one thing that is responsible for flushing is the toilet. With this in mind, we can safely assume that problems with flushing mean poor venting in the majority of cases. Obstructions from a different fixture can end up plugging the drain pipe. In this case we can get rid of the problem with a plumber snake. You will have to put it inside the clean out before the pipe reaches your toilet. Some homes will only have an access point on the roof. Pay very high attention when doing anything on the roof and use all the safety procedures required.
If we are dealing with toilet pressure that simply can not be fixed, as there are different problems that can not be handled with regular solutions, the only alternative stands in a power flush toilet. Unfortunately, they are very expensive and do make a lot of noise. On the other hand, if you do the maths and you find that this option is cheaper and supportable when compared with the alternatives, you could go for it. Also, keep in mind that many toilets that are built with a 4 inch pipe end up reduced to 3 inch for the septic tanks. Such an action will immediately cause suction problems that can easily be misinterpreted as low toilet pressure to the untrained eye.
If the toilet is not filling up properly we might also be faced with improper plumbing. In such a case there might be a need for some modifications done so that pressure is not lost. You have to consult a specialist, get a diagnosis and do the necessary changes if you have enough money. There is also the possibility that the toilet is broken, something that would be easy to fix.