Building permits, zoning and land rules in Peru, Illinois

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

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

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.