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Carroll County, MD Landscaping Rules: Rainwater Harvesting (2026)

Light Restrictions
Compiled from the official code textEditor Martyn O'NeillLast verified September 2026

Key Facts

Governing section
§ 151.036(B)(2)(b)
Applies to
Unincorporated Carroll County only
Practice type
Microscale nonstructural ESD practice
Homeowner exemption
Additions & disturbances under 5,000 sq ft
Recording requirement
Must be recorded in Land Records
Max criminal fine
$50,000 plus up to 1 year jail
Civil penalty
Up to $10,000 per day

Summary

Carroll County doesn't license a backyard rain barrel, but its stormwater code names rainwater harvesting as an approved way to meet development stormwater rules. Section 151.036 lists it as a recognized "microscale" practice, and the chapter reaches only the unincorporated county, not towns like Westminster with their own programs.

These county ordinances apply to unincorporated areas of Carroll County. Incorporated cities within the county may have their own rules that take precedence over county-level regulations.

(b) Microscale (nonstructural). Microscale practices may only be applied to manage the drainage from limited amounts of impervious surfaces. The Manual and Supplement list the restrictions on their use in the county. 1. Swales; 2. Landscape infiltration; 3. Micro-bioretention; 4. Rain gardens; 5. Enhanced filters for divisions (B)(2)(b)3 and (B)(2)(b)4 above; 6. Rainwater harvesting; 7. Submerged gravel wetlands; and 8. Infiltration berms.

View official code

Official source re-checked September 7, 2026: no newer edition of the code had been published (publisher’s edition: 2026 S-15: Supplement contains: Local legislation current through July 30, 2026).

Full Breakdown

035. 036(B)(2)(b) lists rainwater harvesting alongside swales, landscape infiltration, micro-bioretention, rain gardens, submerged gravel wetlands and infiltration berms, and states that microscale practices "may only be applied to manage the drainage from limited amounts of impervious surfaces," with the restrictions on their use spelled out in the Maryland Stormwater Design Manual and the county's own Supplement, published by the Carroll County Bureau of Resource Management. 001(B); incorporated municipalities inside Carroll County run their own separate stormwater programs. 016 exempts additions to existing single-family detached homes and any project that disturbs less than 5,000 square feet of land.

036(B)(5) requires the practice to be recorded in the county's Land Records and kept unaltered by later property owners, with prior county approval needed before it can be modified. 001(B).

Violations & Fines

Failing to install or maintain an approved stormwater practice, including a rainwater harvesting system credited on an approved plan, is a misdemeanor under § 151.999(A): a conviction carries a fine of up to $50,000, imprisonment up to one year, or both, and each day a violation continues is a separate offense. The county may also seek a civil penalty of up to $10,000 per day under § 151.999(B), plus injunctive relief or a corrective-work lien against the property if a Notice of Violation isn't resolved within 30 days.

Frequently Asked Questions

Does Carroll County require a permit for a residential rain barrel?
No. Under § 151.016, additions to an existing single-family detached home and any project disturbing less than 5,000 square feet of land are exempt from Chapter 151's stormwater management requirements, so a typical backyard rain barrel or cistern needs no county stormwater permit.
What does § 151.036 actually say about rainwater harvesting?
It lists rainwater harvesting as one of eight "microscale (nonstructural)" ESD practices a developer may use to meet the county's minimum stormwater control requirements, alongside rain gardens, swales and infiltration berms, limited to managing runoff from limited amounts of impervious surface.
Does this rule apply inside Westminster or other towns in the county?
No. Section 151.001(B) limits Chapter 151 to "the unincorporated areas of the county." Carroll County's incorporated municipalities, including Westminster, administer their own separate stormwater management programs outside this chapter.
What happens if an approved rainwater harvesting system is altered without approval?
Section 151.036(B)(5) requires ESD practices credited toward a project's stormwater compliance to be recorded in the county's Land Records and left unaltered; owners need prior county approval before modifying them, or they risk a Notice of Violation and the penalties under § 151.999.

Sources & Official References

Other rules in Carroll County

All Carroll County rules

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