. Currently, concrete water tank with ”cast in situ” method has still been using conventional technology and needed long construction schedule. This novel research innovates concrete water tank with ”precast” method which corresponds to Indonesian Standard (SNI) and is able to compete in open market price. The stage of the research begun with an investigation to an existing plant of concrete water tank and testing of characteristic analysis of concrete material and precast panels with variety diameter of wiremess steel as reinforcement. Structural strengths of concrete panels were measured by compression and bending moment tests. The diameter of wiremess steel was decided through optimisation in which concrete water tank is significantly safe if burried beneath a family private garage. Then, an economy feasibility study to measure basic production costs was accomplished and this was compared with the normal price of open market. The research found that concrete panels fulfilled SNI with 25,8 MPa in compression strength test, the lowest bending moment was 157,23 kg.m for panels with 2,6 mm diameter of wiremess steel. This concrete water tank was safe when burried beneath a family private garage with safety factor of 187%. The price of 1000 litre of concrete water tank in Yogyakarta was Rp 1.300.000,00 in which it can compete with conventional concrete water tanks by price of Rp 1.350.000,00 and stainless steel water tanks by price of Rp 2.125.000,00.