Zoning, building permits and septic rules in Monmouth, Illinois

Monmouth’s own rules

• Building permitRequired

  Residential solar energy systems inside Monmouth city only; general construction permit rule not opened

  • Site plan required

  “Solar energy systems will require a building permit and shall provide a site plan showing the location of the system on the building or roof.”

• Local zoningPresent

  Land inside Monmouth city limits

  • Code refers to R-1, R-2, B-1, B-4, M-1 and M-2 districts; full zoning ordinance text not opened.

  “in any M-1, limited manufacturing district, or M-2, general manufacturing district, as designated by the City's current zoning ordinance.”

• Manufactured homesLimited

  Placing a mobile/manufactured home in R-2 zone inside Monmouth city

  • Council has granted special uses/variances case by case; base zoning rule not opened.

  required lot width cited in 2007 variance: 50 feet (nonconforming 47-foot lot variance granted)

  “Granting a variance to place a 20-foot × 50-foot mobile home on a nonconforming lot that is 47 feet wide rather than the required 50 feet and a special use variance to place a mobile home in a R2 zone”

• Shed and accessory-building permit exemptionConditional

  Backyard hen coops inside Monmouth city

  • Only for licensed urban hen keeping
  • Coop max 120 sq ft total
  • Min 4 sq ft per hen

  max coop size: <= 120 square feet

  “A minimum of four square feet per hen, but the coop cannot exceed a total of 120 square feet for all six hens. No building permit is required;”

• Subdividing landRegulated (with conditions)

  New subdivisions inside Monmouth city (floodplain standards)

  • Subdivision ordinance itself not opened

  “New subdivisions, manufactured home parks, annexation agreements, planned unit developments, and additions to manufactured home parks and subdivisions shall meet the damage prevention and building protections standards of sections 155.06 and 155.07 of this chapter.”

• Building in a floodplainRequired

  Buildings in the floodplain inside Monmouth city

  • Applies to new buildings, substantial improvements, manufactured homes, RVs on site over 180 days/year
  • State permit requirements of 155.06 also apply

  RV on-site threshold: > 180 days per year

  “all buildings located in the floodplain shall be protected from flood damage below the flood protection elevation.”

Still unanswered

We looked and could not find an official answer yet. Silence is not permission; ask Monmouth or Warren County directly.

• Owner-builder exemption — Monmouth city
• Building code adopted — Monmouth city
• Inspections — Monmouth city
• Certificate of occupancy — Monmouth city
• Minimum dwelling size — Monmouth city R-1/R-2

Each answer was extracted from an official source and independently re-checked against that source by a second reviewer. That is an evidence check, not legal advice. Rules change; confirm with the authority before you buy or build.