The majority of the heavy metals form dark coloured or black sulphides after addition of hydrogen sulphide. The colour differs slightly from element to element. In diluted solutions the heavy metal sulphides don't precipitate, but keep in a colloid state. The so produced dark colour is a measure for the content of a definite heavy metal in water. Even rather insoluble heavy metal compounds can be covered by the described test. For in most cases the heavy metal sulphide is more insoluble, than other salts of the same metal. In most cases of certain sorts of water or waste water it is known from the origin of the water which heavy metal can be present. Thus any analysis may aim at the specific heavy metal. Procedure of the test: Standard solutions of a salt of the heavy metal concerned are prepared, filled in a cylindrical tube, and hydrogen sulphide or a solution of sodium sulphide is added. As test tubes so-called colorimetry cylinders are suitable, or graduated cylinders by substitution. The limit of determination lies at 0,05 to 1 mg/L, depending on the heavy metal and the height of the tube. The appropriate pH must be considered. The solution should be weak acid to precipitate Cu, Pb, or As, neutral, if Fe, Ni, or Co may be present, and weak alkaline in the case of Mn. Furthermore most of the other heavy metals yield dark colours. Only Zn is not to be determined colorimetrically, for its sulphide is white. The described test can be applied as a screening test preceding an instrumental analysis like AAS, ICP-OES, Polarography or others. The test also can be applied as a field analysis in the open air by the side of a sewage channel or a river, because only few and simple equipment are necessary. Supposing the possible present heavy metal is unknown, the test can be modified after the rules of classic qualitative analysis. First precipitation, for example, can be carried out in acid solution. If a dark colour appears, the water is filtered by membrane technique. After neutralization a second sulphide precipitation is proved. On the other hand, colorimetric test can be attached to recognize the present heavy metal in solution, e.g. addition of ammonia as a test for copper or addition of diacetydioxime as a test for nickel. The described test was known in a similar version about 100 years ago in water analysis, but fell into oblivion since better and more exact, but at the same time more expensive methods were introduced. It should be applied again to save money and time.