The Harris County Household Hazardous Waste Facility is at 6900 Hahl Road, Houston 77040, with the entrance on Hahl Road near the junction of Highway 290 and Gessner. It is run by the Office of the County Engineer and it exists for the material no ordinary dump will take - paint, household chemicals, automotive fluids, batteries, fluorescent tubes and similar.

There is a catch in the eligibility rule that its Houston postal address disguises. The facility serves residents of Harris County who live outside the incorporated City of Houston - specifically people who do not receive City of Houston water, refuse and recycling services and do not pay City of Houston taxes. If you are inside the city limits you cannot use it, whatever your address says.

For those who do qualify the service is free. It is also strictly appointment-only: you book a slot online before you go, and there is no walk-up option. Slots run on Tuesdays and Wednesdays between 9 a.m. and 3 p.m., plus two Saturdays a month - the second and the fourth - from 9 a.m. until 2 p.m.

Only material used in your own home for personal purposes is accepted - anything generated by a business falls under a separate programme. The county publishes a full accepted and not-accepted list alongside guidance on transporting chemicals safely, and it is worth reading before you load the car.

Two closure notes. The facility shuts for the whole of Thanksgiving week, Christmas week and New Year week, and it can close at short notice in bad weather - the recorded closure line is 346-286-4294. General enquiries are on 346-286-4299, or 346-286-4296 in Spanish. If you miss the site entirely, the county also runs HazMobile collection events each spring and autumn in every precinct.