Which measurement in water analysis is the sum of both dissolved and undissolved solids?

• A. Suspended Solids
• B. Total Suspended Solids
• C. Dissolved Solids
• D. Total Solids

Answer: (D)

Total Solids represents the amount of all solids present in the water, both those dissolved in the liquid and those that remain as solid particles. When you dry a water sample to a constant weight, every solid component leaves a residue, regardless of whether it was dissolved or suspended; that residue is the total solids. Dissolved solids are only the dissolved portion that passes through a filter and is measured after evaporation of the filtrate, while suspended solids are the particles that are retained on a filter and not dissolved. Total Suspended Solids, then, accounts only for the solids captured on the filter, not the dissolved portion. Since total solids include both the dissolved and undissolved components, it is the measurement that sums everything present.