Plumbing Checklist for Homebuyers Buying a home is stressful and expensive. The last thing you need is an unexpected plumbing repair or upgrade. Did You Know? Average family of 4 used 400 gallons of water a day More than 25% of that comes from flushing the toilet Almost 14% of water use comes from leaks What To Look For Clogging Is For Danes - Flush the toilet in each bathroom. Under Pressure -Test all showers’ water pressure by turning them on.