Proposed water is nothing but the water which selected for mixing of cement or construction purpose.Generally we use regionally available water it can be marine water or it can be chemically impure water or it can be normal water which contain ph of 6 to 8 also.If it is a marine water or chemically impure water it can damage our structure so we compare it's strength with the distilled water.If the resulting strength is related to the distilled water it can be used in our construction.