As the other commenter mentioned, you can buy at-home testing kits. But what you really want is to hire a lead testing and remediation company. We also live in

As the other commenter mentioned, you can buy at-home testing kits. But what you really want is to hire a lead testing and remediation company. We also live in an old house and we spent a huge amount of time applying "lead block" paint and replacing older windows (disastrous for lead dust because of the friction) and some older pipes. You may also want to test your outdoor soil, because older houses near roads will accumulate lead paint in soil due to years of traffic fumes, plus lead dust from the exterior of the house. Kids will sometimes eat dirt, don't ask me how I know. (Also: regular blood lead tests for your young kids! If you live in an older city this will be standard.) Also if you do any construction that disturbs old paint (demolition, window replacement) be careful to seal off the area using plastic, then clean it carefully with disposable wipes.