fortunately in almost every building, we have access to water and water disposal on each floor, otherwise, true, a portable would be a potential problem, but in the few cases where the operator fill have to go up and down to empty and refill, we considered it still worthwhile using a portable, its more a question of productivity and to be honest, its looking like the polaris 1200 may be up to the job, unless someone knows better,,,,,,,,,,,