Even with town water, there's apparently a limit on the GPM the town is supplying. If the pump is doing more than the town is supplying, there will be problems.
If the town water pressure is not enough to fill your tinaco then you need the cistern. A pump off the city water line will cavitate if the pump puts out more water than the town supplies. Enough water pressure and you do not need a pump for your household water needs as in most North American town and cities.
