Rainwater laws / Maryland
Is it legal to collect rainwater in Maryland?
Checked at Maryland's own statutes and agencies, November 2026. Not legal advice.
Allowed; plumbing rules for indoor use
Yes. Maryland's plumbing code (COMAR 09.20.01) includes an appendix covering non-potable and potable rainwater catchment systems.
Before you buy a big tank
State law is only one layer. Cities and counties can set their own rules, especially for tanks plumbed into the house, and an HOA can limit where a barrel sits. Drinking rainwater needs treatment everywhere. For a barrel or two on a downspout for the garden, the state rule above is usually the one that matters.
Where the numbers come from
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