Most large water supply PPP projects are characterised by an initial construction phase followed by an extended operating phase. Typically, usage of an infrastructure facility starts at a low level and builds up over time to the full capacity of the facility. It is more efficient to phase the facility development to match the growth in consumers, but this is usually only partly feasible.
If a project's financial viability is compromised by low initial volumes, a well-targeted means of correcting this is for the LGU to provide an annual support payment up to a certain level of volume. This support takes the form of a guarantee of minimum consumption, and is usually restricted to the early years of a project. If consumption volumes exceed the guaranteed minimum no payment is made. After a certain number of years, usually the time it takes a project to achieve sustainable profits, a claw back mechanism can operate to return the original guaranteed payments to the LGU.