Plastic bio-sand filter is a prototype of a slow sand filter which purifies water using sand and gravels of specific sizes of (0.36mm, 2.36mm, 6.35mm), this filter has been designed and constructed to evaluate its performance using raw water from fishpond at faculty of Engineering, Ahmadu Bello University Zaria and to remove pathogenic organisms present in the water. The filter is composed of a lid which covers the whole filter from the entrance of debris or contaminants, a perforated plastic called a diffuser which prevents the disturbance of the sand layer when water is poured into the filter and contain activated carbon which removes taste and odor, dredged sand of effective size of 0.38mm and uniformity coefficient of 1.47 from the reservoir at A.B.U dam which trap in pathogens and suspended solids, and gravel layers which supports the filtration sand and help water to flow into the outlet tube. After conducting an

experiment using the raw water from fishpond, the filter effectively reduce the taste and odor and bacteria count from (95 to 6) MPN, the turbidity from (43.7 to 1.27) NTU, settleable solids from (0.95 to 0.11) ml, total suspended solids from (1.35 to 0.12) mg/l, total dissolved solids from (7.99 to 0.48) mg/l, and total solids from (9.10 to 0.65) mg/l.