In order to obtain a comparatively pure water-supply, under circumstances existent in most bazaars, it is essential that the spill water from wells be led away by properly constructed drains beyond what is known as the cone of filtration; this may be described as a circle drawn round the mouth of the well, the radius being equal to the depth of it. Owing to Indian customs, there is always a considerable quantity of spill water in the vicinity of a well, and this, when proper platforms and drains are not constructed, finds its way back, after contamination, by the line of least resistance, either down the sides of the masonry lining, or by cracks and fissures in the ground. For water supplies from wells and tanks the main object is to prevent any water once drawn out, again, after probable contamination, flowing back into the source of supply. Arrangements should be made for registering every well in a municipality where this has not already been done, and for taking over, or closing all those the owners refuse, or fail to put in a proper sanitary state. In Bengal this can be enforced under section 200 of the Bengal Municipal Act (1894). A copy of the map of a ward showing the position of all wells and tanks therein is given in Fig. 3. The Well Register, which should be corrected yearly, is given in Appendix C, page 62. It is impossible in most cases, owing to large numbers, for a Municipality to take over, repair, and conserve all the wells (in the town of Muzaffarpur, there were 718 wells) but much good can be done by acquiring a certain number of the most useful unowned ones, and making the owners of others, when in a position to do so, put and maintain them in a sanitary state. When new wells are sunk, the owner must be made to construct them according to a standard design. Fig. 4 shows an inexpensive and good form of open well, top, and platform. From the experience of ten years in the Muzaffarpur District (from 1891 to 1901), where wells on the sides of main roads were so treated, this is possible. Some 400 wells on 725 miles of road were taken over by the District Board, put in a proper state of repair, suitable platforms and spill-water drains constructed, and arrangements made for annual cleaning out and disinfecting with permanganate of potash during the hot weather months. These were eventually greatly appreciated, and, whereas in the first instance difficulties were experienced in getting hold of suitable ones, it was of late years necessary to make careful selections from the applications received. In addition to this, the owners of numerous ones, on whom notice was served that if they did not put them in a sanitary condition, they would be taken over and repaired by the District Board, elected to do the work on the prescribed lines at their own expense. It is a notable fact that cholera when prevalent in villages close by, frequently is not found in those where these wells are situated.