The 401 Waterloo Multilevel System allows detailed groundwater monitoring from many zones in one borehole. The System is modular to allow ports to be located accurately at desired monitoring zones. The zones are permanently isolated by packers or seals and each port is individually connected to the surface. Ports can be fitted with dedicated Transducers, Bladder Pumps and/or Double Valve Pumps. Alternatively, a port may be fitted with open tubes for monitoring with portable, narrow diameter instruments.