Bolthole Index

LaSalle County, Illinois

Building permits, zoning and land rules in Peru, Illinois

Peru, Illinois requires building permits for new homes through the City Building and Zoning Department.1 Peru sets its own zoning inside city limits, while LaSalle County Health Department handles private septic permits and inspections.23 RV dwelling occupancy in Peru is prohibited except in lawfully established mobile home parks or tourist camps.4

At a glance

Building permits
City building permits required for new homes and structural work1
Zoning
Peru zoning applies inside city limits2
Private septic
LaSalle County Health Department permits installations and repairs35
RV living
Dwelling occupancy prohibited except in lawful mobile home parks or tourist camps4
Residential lot size
R-1 minimum: 15,000 square feet for interior lots; 18,000 for corner lots6
Water and sewer connections
City connection permit required for water and sewer services7

Who to call

Building permits

City of Peru Building and Zoning Department

City construction plan review, building permits, zoning questions and field inspections

(815) 224-6020

1901 4th Street Peru, IL 61354

Building permits

City of Peru Building Permit Information

Project-specific building permit requirements, application information and related city connection and street permits

Septic permits

LaSalle County Health Department Sewage Disposal Program

Private sewage disposal system installation and repair permits and inspections

Health department

LaSalle County Health Department

Contact the department for Environmental Health assistance with private septic systems and wells

815-433-3366

717 E Etna Road Ottawa , IL 61350

Contact details are copied from each office’s official page and were checked against it on October 11, 2026.

Off-grid gear

Going off-grid in Peru means bringing your own water and power. The kit we’d start with:

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Do you need a building permit in Peru, IL?

Peru requires a city building permit for every new home, structural work, room additions, basements, decks and sheds or garages.1 The City Building and Zoning Department reviews plans and conducts construction field inspections.8 Peru has adopted the 2018 International Residential Code for one- and two-family dwellings, with city amendments.9 Ask the department which code provisions and inspections apply to your design before submitting plans.8

Peru residential applications must include a drawing showing the intended building location dimensioned from all lot lines, and a site plan must be approved before the building permit is issued.7

Who issues building permits and zoning approval in Peru?

Contact the City of Peru Building and Zoning Department at (815) 224-6020 for city construction plan review, building permits and inspections.8 The department address is 1901 4th Street Peru, IL 61354.8 Bring the proposed use and a drawing of the building location so the city can address the residential application requirements.7

Peru generally takes 2 weeks to review and process permit applications, but required changes can extend that period.7 Treat that published review period as a planning allowance rather than an approval guarantee.7

Does Peru have zoning, and what lot size is required?

Peru has municipal zoning regulating land use and structures inside city limits.2 In Peru’s R-1 Single-Family Detached Dwelling District, minimum lot area is 15,000 square feet for interior lots and 18,000 square feet for corner lots.6 Those are R-1 requirements, so ask the City Building and Zoning Department to identify the district for the parcel before using those dimensions in a purchase decision.68

Peru’s zoning ordinance also states that it covers the city’s extraterritorial jurisdiction; for land near the city boundary, ask the city to identify the applicable zoning authority.2

How do private septic permits work inside Peru?

LaSalle County Health Department handles private sewage disposal permits and inspections for installations and repairs.310 The county application requires a completed application, fee and onsite survey before a septic construction permit is issued; the stated fee is $230 and is returned if the permit is denied.5 Contact the Health Department at 815-433-3366 about a proposed private system.11

Protect the designated sewage-disposal area from construction traffic, compaction and soil changes, and notify the Health Department for final inspection before backfilling.12 A compost toilet does not eliminate wastewater disposal requirements: Illinois requires other domestic wastes to go into a conventional private sewage disposal system under its off-grid sanitation rule.13

Can you live in an RV or tiny home in Peru?

Peru prohibits occupancy of mobile homes, motorized homes, travel trailers and camping trailers for dwelling purposes, except in lawfully established mobile home parks or tourist camps.4 Peru allows limited camping-trailer parking or storage in residence districts subject to its zoning conditions, but that storage provision does not authorize dwelling occupancy.14 Plan alternative accommodation while a home is under construction rather than relying on an RV on the building lot.4

We could not confirm a Peru rule specifically authorizing tiny-home occupancy or accessory dwelling units; take the intended size, foundation and use to the City Building and Zoning Department for a project-specific answer.8

Building a home in Peru: what are the steps, in order?

  1. Ask the City Building and Zoning Department to confirm the proposed use and the parcel’s zoning district.28
  2. Prepare the residential location drawing with dimensions from every lot line and obtain site-plan approval before the building permit.7
  3. Resolve sanitation: obtain the county septic permit for a private system, or the city connection permit for water and sewer services.57
  4. Obtain the city building permit and arrange required construction inspections through Building and Zoning.81
  5. Obtain a street permit for work in the city street right-of-way, and account for Peru’s permanent driveway-surface deadline after the occupancy permit.715

What should you check before buying land in Peru?

Ask Peru Building and Zoning to confirm city limits, the proposed use and the applicable district before buying a parcel for a home.28 For land outside Peru, consult the LaSalle County guide for the county’s unincorporated-area zoning rules, and ask Peru about any extraterritorial zoning overlap.162

For a subdivision subject to Peru’s floodplain article, the city requires floodplain information and a licensed engineer’s drainage statement.17 Water and sewer services require city connection permits; we could not confirm the threshold requiring a new home to connect when public service is available, so ask Building and Zoning about the proposed address.78

Watch-outs

  • Parking or storing a camping trailer in a Peru residence district does not authorize dwelling occupancy.14
  • Peru residential driveway surfaces must be permanently installed within 6 months after issuance of an occupancy permit.15
  • We could not confirm a general Peru owner-builder exemption, tiny-home occupancy rule or complete current city permit-fee schedule; ask the City Building and Zoning Department before committing to a project.8

Sources

  1. City of Peru Building Permit Information (peru.il.us)
  2. City of Peru Zoning Ordinance (Peru), quoted and re-checked
  3. Sewage Disposal, quoted and re-checked
  4. City of Peru Zoning Ordinance, section 4.05 (Peru), quoted and re-checked
  5. Sewage Disposal, quoted and re-checked
  6. City of Peru Zoning Ordinance (Peru), quoted and re-checked
  7. Building Permit Information - City of Peru (Peru), quoted and re-checked
  8. City of Peru Building and Zoning Department (peru.il.us)
  9. Adoption of International Residential Code for one- and two-family dwellings (Peru), quoted and re-checked
  10. LaSalle County Health Department Sewage Disposal Program (lasallecountyil.gov)
  11. LaSalle County Health Department (lasallecountyil.gov)
  12. Private Sewage Disposal Permit Application, quoted and re-checked
  13. 77 Ill. Adm. Code 905.130 Human Waste Disposal (Illinois statewide rule), quoted and re-checked
  14. City of Peru Zoning Ordinance, section 4.05 (Peru), quoted and re-checked
  15. City of Peru Zoning Ordinance (Peru), quoted and re-checked
  16. Land Use Department | LaSalle County, IL, quoted and re-checked
  17. Floodplain subdivision requirements (Peru), quoted and re-checked

Written October 11, 2026 from the rules quoted below, each taken from an official source and re-checked by an independent reviewer. This is research, not legal advice: rules change, so confirm with the office before you buy or build.

Answers from the rulebook for Peru

Peru’s own rules

  • Building permitRequired

    Property where work subject to IRC Sec. R105.1 is performed inside Peru city.

    • Work done without the required permit must be regularized through an after-the-fact application and permit.
    • The provision expressly refers to permits required by IRC Sec. R105.1.
    “work has been done without the required permit having been first obtained as required by Section R105.1”
  • Building code adoptedAdopted (with conditions)

    One- and two-family dwellings inside Peru city.

    • The adopted 2018 IRC is amended by Sec. 22-39.
    • The ordinance identifies the code as the City of Peru Residential Code.

    IRC edition: 2018 (Amended by Sec. 22-39)

    “The 2018 edition of the International Residential Code for one- and two-family dwellings [...] is hereby adopted by reference by the City of Peru, Illinois”
    One more reviewed finding on this topic
  • InspectionsLimited

    Property inside Peru city where work was done without the required permit.

    • The owner must allow a building-code-compliance inspection.
    • The owner must obtain a permit to correct deficiencies noted in that inspection.
    • After-the-fact permits and compliance inspections are subject to double permit and inspection fees established in the Code of Ordinances.

    after-the-fact permit and inspection fee multiplier: 2 times (Applies to fees established in the Code of Ordinances)

    “the property owner shall allow the engineering and zoning department to conduct a building code compliance inspection”
    One more reviewed finding on this topic
  • Certificate of occupancyLimited

    A building inside Peru city whose use or occupancy is changed.

    • A certificate may not issue unless the building substantially complies with Chapter 22.
    • The engineering and zoning director may issue a temporary certificate before all permitted work is complete if the occupied portion is safe, for a period set by the director.
    “The use or occupancy of any building shall not be change until a certificate of occupancy permitting the new use or occupancy is issued”
  • Local zoningPresent (with conditions)

    Land inside the City of Peru, Illinois.

    • The cited property-maintenance code preserves provisions of the City of Peru Zoning Code.
    “Nothing in this code shall be construed to cancel, modify or set aside any provision of the City of Peru Zoning Code.”
    One more reviewed finding on this topic
    • Present — Land inside Peru city limits; the ordinance also states that it covers the City's 1.5-mile extraterritorial jurisdiction.
      “regulates land use and structures in the City of Peru”
  • Minimum lot sizeSpecified

    R-1 Single-Family Detached Dwelling District inside Peru city limits.

    • Interior lots require 15,000 square feet.
    • Corner lots require 18,000 square feet.
    • Minimum width is 100 feet for interior lots and 125 feet for corner lots.
    • Cul-de-sac lot width is 80 feet measured by arc distance.

    interior-lot area: 15000 sq ft · corner-lot area: 18000 sq ft

    “Minimum lot area. Fi�een thousand (15,000) square feet, except for corner lots which shall be eighteen thousand (18,000) square feet.”
  • Living in an RVLimited

    Travel trailers and recreational vehicles on a site in a Peru city floodplain for more than 180 days per year.

    • The cited section applies to buildings located in the floodplain.
    • Installing a travel trailer or recreational vehicle on a site for more than 180 days per year triggers building-protection requirements.
    • Travel trailers and recreational vehicles on site for more than 180 days per year must meet the cited elevation requirements unless the section's subsequent exceptions apply.

    site duration threshold: > 180 days per year (Floodplain rule)

    “Travel trailers and recreational vehicles on site for more than 180 days per year shall meet the elevation requirements of subsection (d)”
    One more reviewed finding on this topic
    • Prohibited — Occupancy of mobile homes, motorized homes, travel trailers, or camping trailers as dwellings on land inside Peru city limits.
      “shall not be occupied for dwelling purposes”
  • Camping on your landLimited

    Temporary camping-trailer storage or occupancy inside Peru city limits.

    • Camping trailers may not be occupied for dwelling purposes except in lawfully established mobile home parks or tourist camps.
    • One camping trailer may be parked or stored in a residence district only if it conforms to paragraph 7.03(d)(1)c.
    • Small recreational tents may be used on the same lot as a dwelling.
    • Other temporary tent uses require a Building Inspector permit.

    camping trailers in residence district: <= 1 trailer (must conform to paragraph 7.03(d)(1)c)

    “No more than one camping trailer may be parked or stored in the open or within an enclosed structure on a lot in a residence district, and only when it is in conformance with paragraph 7.03(d)(1)c of this ordinance.”
  • Manufactured homesLimited

    Manufactured homes installed on a new site or as a new manufactured home on an existing site in a Peru city floodplain.

    • The building-protection rule applies to buildings located in the floodplain.
    • The section excludes returning a manufactured home to the same site it lawfully occupied before removal to avoid flood damage.
    • Manufactured homes permanently installed on site must be elevated to or above the flood-protection elevation and anchored under the Illinois Mobile Home Tie-Down Act rules.
    “Manufactured homes or travel trailers to be permanently installed on site shall be: (1) Elevated to or above the flood protection elevation”
  • Mandatory utility hookupConditional

    Connection of a building sewer to the City of Peru public sewerage system.

    • A written City permit is required before making or using a public-sewer connection.
    • A building-sewer permit and connection are allowed only if downstream sewers, pump stations, and the POTW have sufficient reserve capacity.
    • The owner and permittee bear all installation and connection costs and indemnify the City.
    • The supplied sections do not establish a general mandate to connect a new home to public water or sewer when available.
    “No unauthorized person shall [...] make any connections with [...] any public sewer or appurtenance thereof without first obtaining a written permit from the City of Peru.”
  • Subdividing landRegulated (with conditions)

    New subdivisions, manufactured-home parks, annexation agreements, planned unit developments, and additions to manufactured-home parks and subdivisions inside Peru city where the floodplain ordinance applies.

    • The proposal must meet Secs. 46-31 and 46-32 damage-prevention and building-protection standards.
    • A proposal must include base-flood elevation and floodplain-boundary data, floodway boundaries when applicable, and a licensed-engineer statement addressing surface-water drainage under the Plat Act.
    • The City must take known hazards into account in official land-management, use, and development actions.
    “New subdivisions [...] shall meet the damage prevention and building protections standards of sections 46-31 and 46-32 of this article.”
    One more reviewed finding on this topic
    • Regulated (with conditions) — New subdivisions, manufactured-home parks, annexation agreements, planned unit developments, and additions to manufactured-home parks or subdivisions inside Peru city limits when subject to the City's floodplain article.
      “New subdivisions, manufactured home parks, annexation agreements, planned unit developments”
  • Driveway accessRequired

    Residential driveways and parking access inside Peru city limits.

    • A permanently installed driveway surface must be installed within six months after issuance of an occupancy permit in residential zoning districts.
    • Residential driveway widths in the public right-of-way must be at least 9 feet and are subject to maximum widths based on garage capacity.
    • The acute angle at the street intersection must be at least 60 degrees.
    • On corner lots, the nearest driveway edge must be at least 15 feet from the adjacent intersection street right-of-way line.

    minimum residential driveway width: >= 9 feet (measured at property line) · driveway surface deadline: 6 months (after occupancy permit issuance)

    “In all residen�al zoning districts, a permanently installed driveway surface in accordance with the requirements of Sec�on 7.04(a) shall be installed within six months a�er issuance of occupancy permit.”
  • Building in a floodplainRequired

    Buildings and development located in a Peru city floodplain.

    • The floodplain includes lands within City jurisdiction that are subject to base-flood inundation.
    • The provision is in addition to state permit and damage-prevention requirements under Sec. 46-31.
    • New buildings, specified construction or alterations, substantial improvements, repairs to substantially damaged buildings, new manufactured-home installation, and RV or travel-trailer installation exceeding 180 days per year are among the listed triggering situations.

    RV or travel-trailer floodplain site duration: > 180 days per year (Triggers stated building-protection requirements)

    “all buildings located in the floodplain shall be protected from flood damage below the flood protection elevation.”
  • Permit feesPublished (with conditions)

    Applications for utility construction permits in City rights-of-way inside Peru city.

    • The $100 application fee applies unless a franchise, license, or similar agreement provides otherwise.
    • An electricity utility paying the municipal electricity infrastructure maintenance fee is exempt from the application fee.
    • This source does not establish City building-, zoning-, development-, water-, or sewer-connection fee schedules.

    right-of-way utility permit application fee: 100 USD (Unless otherwise provided by franchise, license, or similar agreement; electricity utilities paying the municipal electricity infrastructure maintenance fee are exempt)

    “Unless otherwise provided by franchise, license, or similar agreement, all applications for permits pursuant to this article shall be accompanied by a fee in the amount of $100.00.”
  • Permit processPublished (with conditions)

    Building and related permit applications inside Peru city limits.

    • Residential applications require a drawing showing the intended building location dimensioned from all lot lines.
    • Commercial and industrial applications require two sets of plans drawn by an Illinois architect or structural engineer.
    • A site plan must be approved before a building permit is issued.
    • Permits generally take two weeks to review and process; changes may extend that period.
    • Water and sewer services require a connection permit, and work in the street right-of-way requires a street permit.

    general permit review time: 2 weeks (changes may require longer)

    “Permits generally takes 2 weeks to review and process.”
    One more reviewed finding on this topic
    • Partial — Earth changes inside Peru city.
      “Unless specifically exempted, an earth change permit [...] shall be obtained from the superintendent of public works prior to the commencement of any excavating, grading, regrading, landfilling, berming, or diking”

Still unanswered

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

  • Owner-builder exemption — Owner-builders performing construction inside Peru city limits.
  • Zoning districts — Zoning districts inside Peru city.
  • Minimum dwelling size — A-1 Agricultural District inside Peru city limits or Peru zoning jurisdiction.
  • Setbacks — Residential zoning districts inside Peru city.
  • Lot coverage — Lots inside Peru city limits.
10 more unanswered
  • Building height
  • Tiny homes
  • Accessory dwellings
  • Who permits septic
  • Septic permit
  • Septic inspection
  • Off-grid sanitation
  • Well permit
  • Agricultural exemption
  • Short-term rentals

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.

Unanswered questions are usually a sign that Peru publishes no rule on the point, not that none exists. LaSalle County’s page lists the county offices to call.

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