Filters can improve the taste and appearance of water, but they do not purify it. These devices must also be kept in good condition or they could lower water quality. Lead pipes and lead soldered pipes are particularly harmful to pregnant women and children. If you have concerns about this problem, have your water analyzed by a certified laboratory. The lead count should not exceed 15 parts per billion.
Water can take a lot of abuse and responds well to treatment.
However, water consumption and water contamination by toxic products are two different things. Obviously, to conserve drinking water, its sources must be treated and preserved as well. Water is re-used over and over and often recycled after use. It may be used again in the same week or not for many years. The amount of water on the planet has remained the same for three billion years.