Are mercury float switches still available, and should I use one?

Mercury float switches have been largely phased out in many regions, but they do still exist (some suppliers carry them). They use a small amount of liquid mercury inside the float as the switching element. Mercury switches are very reliable in terms of not getting stuck (the mercury moves to make the contact) and can handle lots of cycles. However, due to mercury’s toxicity, many places restrict their use or require special disposal. Manufacturers offer mercury-free alternatives (using mechanical ball-bearing switches or magnetic reed switches) that perform similarly without the environmental hazard. If you’re replacing an old mercury float, it’s generally recommended to switch to a mercury-free model unless your locale explicitly still allows and you specifically need the mercury type. In most cases, a high-quality mechanical float will be sufficient. Only consider mercury floats if you have a compelling reason and it’s legal – otherwise, it’s best practice to avoid introducing mercury into a wastewater system.