Buying Land in Boone County: Zoning, Wells and Septic

October 7, 2026

Buying land outside Belvidere means buying a stack of approvals along with the dirt. In unincorporated Boone County, the county decides what can be built on a parcel, the county health department decides whether the well and septic can go where you want them, and the highway authority decides whether you can put a driveway on the road. Zoning has to come first, because the health department's own page says a building permit cannot be issued without proper zoning. A buyer who learns that order before an offer saves a great deal of money and a few bad surprises. This guide covers the county rules for a house on acreage or a vacant parcel outside the city: zoning districts, well and septic approval, building permits, the driveway, and how farmland is assessed. It does not repeat the city of Belvidere's rules, because those apply only inside city limits. If you are comparing country parcels with homes for sale in Belvidere, the first question is which jurisdiction answers for the address, and this article explains how to find out. Gambino Realtors has been in business since 1923 and has worked with buyers on both sides of that line. What County Zoning Allows On Rural Land The county's Planning Department says the Boone County Unified Development Ordinance and Zoning Map were adopted on June 18, 2026. The posted ordinance applies to all land, uses and structures in the unincorporated county, and it also governs a property that has an annexation agreement with a municipality more than 1.5 miles away. One caution belongs up front. The copy of the ordinance posted on the county's site is dated June 23, 2026, and its effective-date line is a blank placeholder. The county building page still links to the older zoning ordinance. So ask the Planning Department at planning@boonecountyil.gov which rules govern your parcel and from what date, and get the answer in writing. The ordinance sorts rural land into districts, and four of them matter to a home buyer. The A-1 Agricultural Preservation District exists to conserve prime farmland and sensitive natural features, and the ordinance says plainly that it is not meant for residential subdivisions. The A-2 Agricultural Residential District allows individual nonfarm homes in areas not historically used for crops or livestock, or unsuited to farming. The R-E Residential Exurban District covers rural residential land that is not expected to have centralized water or sewer. The R-1 District covers more conventional residential development. A single-unit dwelling is a permitted use in all four. The lot sizes differ by district, and they are the first filter. In A-1, a lot for a non-agricultural use needs at least 5 acres and 250 feet of width, with a 75-foot front setback, 15 feet on each side and 35 feet at the rear. In A-2, a residential lot must be at least 2 acres and may not exceed 5 acres, with 250 feet of width and at least 40 feet of road frontage. In R-E, the minimum is 2 acres and 250 feet. In R-1, the minimum is 1 acre and 100 feet of width without public or private sewer and water, and 9,000 square feet and 65 feet with them. Building height is capped at 35 feet in each. When a listing says "5 acres," the district decides what you can do with it. The A-2 conditions, in plain terms A-2 is the district where a buyer is most likely to hear "you can build one house here," so it is worth knowing the conditions. A lot must meet at least one of four tests. It can have a land evaluation score of 69 or lower, meaning it is not prime farmland, as rated by the Boone County Soil and Water Conservation District. It can have a slope over nine percent or be classified as highly erodible land. It can have physical barriers to farming, such as streams, rock outcroppings or wetlands. Or it can have one acre or more with 50 percent or more tree canopy from naturally wooded areas. In addition, the lot must meet every one of three more conditions. It must have safe road access with adequate sight distance, as approved by the County Engineer. It must be suitable for a septic system, as determined by a licensed Illinois soil classifier or professional engineer and approved by the Boone County Health Department. And it needs a site plan showing how much of the property stays open and undeveloped. Read that list as a buyer. If a parcel is flat, farmed and prime, A-2 is probably not the district for it, and a dwelling may depend on a different rule. If a parcel is wooded, sloped or wet, those same features can be the reason a house is allowed and also the reason the septic design is hard. The county's own text ties the two together. Older lots and the grandfather rules Many rural parcels were created before today's rules, and the ordinance has a section for them. A lot with a recorded plat when the new ordinance was adopted may be developed under the lot area, width, depth and road frontage rules of the zoning ordinance adopted April 11, 1984, even if it falls short of today's. A lot platted before April 11, 1984 may use the 1973 rules, and a lot platted before July 12, 1973 may use the 1958 rules. In the A-1 district, undeveloped lots of record in lawful existence before May 10, 1978 can be built with one single-unit dwelling per zoning lot if the lot has legal access to a public road or an approved private road and meets the county's other codes. The section ends with a line every buyer should underline. The owner is still required to provide an adequate sewage treatment system. Two other grandfather points matter. If you own two or more adjoining substandard lots, the ordinance requires them to be developed as one, and no permit will be issued otherwise. And in A-1, a house on a lot divided off before May 10, 1978 is a legal nonconforming lot. If that house is damaged or destroyed, it can be rebuilt only under the current A-1 bulk and setback rules, with an exception for a house that sat at least 200 feet back from the front lot line. Ask what category the parcel falls in before you assume a rule applies. The ordinance also makes room for outbuildings. Accessory structures cannot go up before the principal building, and they are not allowed in an easement. In A-1 and A-2, the usual 50 percent rear-yard cap on accessory buildings does not apply, and height follows the principal building limit. In R-E and R-1, a structure of 200 square feet or less needs a 5-foot setback from lot lines, a larger one needs 15 feet, and the height limit is 20 feet. An accessory dwelling unit is allowed in all four districts on a lot with a single-unit dwelling, one per lot, up to 1,000 square feet and two bedrooms. It has to share the home's septic system or have an independent system sized for two bedrooms. Zoning also leaves room for farming itself. The ordinance says its zoning provisions are not applied to land used for agricultural purposes except to the extent state law authorizes, so a working farm and a house on acreage follow different rules. Wells, Septic And The Health Department Outside the city's water and sewer lines, the house usually has its own well and its own septic system, and the Boone County Health Department regulates both. Its septic page opens with a plain warning. Before you start the process for septic, well, building or zoning permits, check with Planning to confirm the property has the correct zoning, because without proper zoning all the effort spent on the other permits is wasted. The county building page adds that most structures need site plan approval from the Health Department before a building permit is released. For a new septic system or the replacement of a failed field, the first step is soil borings. A certified soil classifier performs them, and the county lists the people qualified to do it. Then the installer or the owner submits a plan drawn to scale, with the proposed house location, an elevation profile, a septic checklist, a waste-stream sheet and a maintenance agreement. The department says review takes about 5 to 10 business days after it receives the plan. Fees are due when the plan goes in. The septic and well permits must be issued before installation or drilling begins, and before the county will issue a building permit. Installation has its own rules. The installer must hold both an Illinois license and a Boone County license. The Health Department must be notified 48 hours before work begins, and no part of the system may be covered until it has been inspected and approved. An owner who installs their own system pays for two additional compliance inspections. If the design includes an aerobic treatment unit that shrinks the field, the owner must sign for an operator's permit and accept its ongoing requirements. A home addition, a pool or another structure that encroaches on the existing field needs its own septic permit, which is the rule that surprises owners planning a pool on a rural lot. Wells run on a similar track. A permit is needed from the Health Department before a well is built, sealed, deepened or modified, and the department must get 48 hours' notice before work starts. A new well must be tested before the water is used, and the first sample is paid for during permit application. After that, the department recommends sampling every year and after any repair. The standard test covers coliform bacteria and nitrates. The standard for coliform is zero. If a sample is positive, the water is considered unsafe to drink, and the department advises boiling it for three minutes or using bottled water until a clean sample comes back. Nitrate has a federal standard of 10 milligrams per liter as nitrogen. Boiling does not remove nitrate and makes the concentration higher. Older rural houses add three more items. An abandoned well must be sealed within 30 days by a licensed well driller, though an owner may seal a well on land used for farming or as a home with a permit, and every homeowner sealing is inspected. Unused septic tanks, dry wells and cisterns have to be properly abandoned and the record sent to the department. And a well in a pit is something to look at closely, because the state's code does not allow new wells in pits, and an existing pit has to be structurally sound and watertight, with the casing at least 12 inches above the pit floor and a watertight cover. The inspection that is not required, and why you should order it The county says plainly that a well and septic evaluation for a real estate transaction is not required by the Health Department. It may be required by your lender or written into your contract, and the department calls it a good idea for liability and to prevent unexpected expenses from repairs. You request it with a form or by calling 815-544-2951, extension 2. The state disclosure report asks the seller about defects in the well, unsafe drinking water and defects in the septic or sewer system, but it covers what the seller knows, and the form says it is not a substitute for an inspection. Our guide to water, sewer and private wells in a neighboring village covers the same questions from a different county's perspective. Permits, The Driveway And How Farmland Is Assessed Building in unincorporated Boone County goes through the county's Building Department, which takes applications through an online system called Cloudpermit. The department's page lists the codes it enforces, including the 2021 International Building and Residential Codes, the 2020 National Electrical Code and the 2014 Illinois Plumbing Code, with local amendments. It also notes that if you live in a subdivision, an association may require its own approvals. The page carries the warning mentioned earlier. If the online system rejects an address, the property may not be in the county's jurisdiction, which usually means it sits inside a city. Confirm that before you spend on plans. The driveway has a separate approval. The Highway Department explains that the townships keep about 60 percent of the rural road mileage, the county about 18 percent, the state about 14 percent and the Toll Highway Authority about 2 percent, with the rest private. Because a driveway puts pavement on public right-of-way, the county says the law requires approval from the appropriate highway authority before you install it. In practice that is the agency that maintains your road, which may be a township, the county or the state. The zoning rules also require adequate sight distance at an A-2 lot's access, as approved by the County Engineer, so a parcel on a hill or a curve may be harder than one on a straight road. Farmland is assessed differently from a house lot, and the difference is large enough to matter. Under Illinois law, a farm means property used solely for growing crops, raising livestock, or similar agricultural use, and the statute says land primarily used for residential purposes does not count as a farm even if some crops or animals are on it. The farm dwelling and the tract immediately around it are assessed at one-third of fair cash value, like other homes. The cropland is assessed by a formula. The Department of Revenue certifies values by soil productivity index each year, and cropland is adjusted for slope, drainage, ponding, flooding and the size and shape of the field. Permanent pasture is assessed at one-third of that cropland value and other farmland at one-sixth. Land managed under an accepted forestry plan is treated as other farmland. A parcel must have been used as a farm for the two preceding years to qualify. The Boone County Assessment Office explains the chain. Township assessors value property first, the county office brings values to one-third of market value using three years of sales, and the Board of Review hears complaints. The office also handles some preferential assessments, including conservation stewardship and the Forestry Act. For a buyer, the point is simple. A parcel that has been taxed as farmland may not stay on that assessment if its use changes, and the tax bill can change. Ask the seller for the bill and ask the Assessment Office what the parcel's classification is and what would change it. Do not assume the current bill is what you will pay. One more county program shapes some rural land. Boone County has two state-recognized agricultural areas, from 1992 and 1995, where owners voluntarily place temporary conservation easements on their land, and the county's planning page says roughly 7,100 acres were enrolled. The county also has a commission that works on permanent agricultural conservation easements, and it recorded its first one in 2009. If a parcel you are considering sits in an agricultural area or carries an easement, ask the Planning Department what that means for building and for resale. The county's page does not give a date for the acreage figure, so ask for the current number. There is a boundary case that deserves a mention. Subdivisions can move from the county to the city. In August 2025, the Belvidere City Council annexed the Deer Hills and Deer Woods II subdivisions north of US Business Route 20, which had not been inside any municipality before. If you are buying in an area near the city limits, check whether the lot has been or is likely to be annexed, because the permitting office, the zoning map and the inspection process change when it happens. Bottom Line Buying acreage near Belvidere means checking five things in order. Confirm the address is in the unincorporated county. Confirm the zoning district and ask Planning which version of the ordinance applies. Confirm the septic soils and the well with the Health Department before you rely on a building permit. Confirm the driveway approval with whichever highway authority owns the road. Then confirm how the parcel is assessed and what would change it. None of this is complicated, but all of it has to happen in the right order, and every step happens before you start digging. If you are ready to compare rural parcels with homes for sale in Belvidere, we can help you ask the county the right questions before you write an offer. The full list of local guides is in the Illinois Real Estate Guide, and our guide to the Illinois seller disclosure report explains the state form that goes with any home purchase. That covers the county rules in order. Here are the questions buyers ask us most about land and acreage outside Belvidere. Frequently Asked Questions Can I build a house on a vacant parcel in unincorporated Boone County? Often yes, but only after several approvals. A single-unit dwelling is a permitted use in the county's A-1, A-2, R-E and R-1 districts, subject to lot size, setback and district conditions. The Health Department must approve the septic and well plans, the highway authority must approve the driveway, and the county building permit follows. The Health Department's page says a building permit cannot be issued without proper zoning, so confirm the zoning first. How many acres do I need for a house in rural Boone County? It depends on the district. Under the posted ordinance, a non-agricultural lot in A-1 needs at least 5 acres. In A-2, a residential lot must be between 2 and 5 acres. R-E requires 2 acres, and R-1 requires 1 acre without sewer and water or 9,000 square feet with them. Older lots of record may be built under earlier rules. Ask the Planning Department which version of the ordinance governs your parcel. Who approves a well and septic system in Boone County? The Boone County Health Department. A well needs a permit before it is built, sealed, deepened or modified, and a new well must be tested before the water is used. A septic system needs soil borings from a certified classifier, a scaled plan, a permit and an inspection before anything is covered. The installer must hold Illinois and Boone County licenses. Call Environmental Health at 815-544-2951, extension 2. Do I need a well and septic inspection when I buy an acreage home? The Health Department does not require one for a sale, but your lender or your contract may, and the department calls it a good idea to prevent unexpected repair costs. You request an evaluation with its Real Estate Inspection Request form or by calling 815-544-2951, extension 2. The seller's disclosure covers only what the seller knows, so the inspection is how you find the rest. How is farmland assessed for property tax in Illinois? Under state law, cropland is assessed by its soil productivity index, adjusted for slope, drainage, flooding and field shape. Permanent pasture is assessed at one-third of the cropland value, and other farmland at one-sixth. The farm dwelling and the tract it sits on are assessed at one-third of fair cash value. Land primarily used for residential purposes does not qualify as a farm, and a parcel generally must have been farmed for two preceding years. Do I need a permit to put a driveway on a rural road in Boone County? Yes. Because a driveway places pavement on public right-of-way, the county says the law requires approval from the appropriate highway authority before you install it. That is the agency that maintains your road, which may be a township, the county or the state. Ask the Boone County Highway Department which authority covers your road, and apply before you begin any work. How do I know if a property is in the city or in the county? Check the zoning and permitting jurisdiction before anything else. The county's building page warns that if its online system rejects an address, the property may not be in its jurisdiction. You can also ask the city's planning department at 815-547-7177 and the county's Planning Department. A property can also be annexed later, as two subdivisions north of US Business Route 20 were in August 2025. { "@context": "https://schema.org", "@type": "FAQPage", "mainEntity": [ {"@type": "Question", "name": "Can I build a house on a vacant parcel in unincorporated Boone County?", "acceptedAnswer": {"@type": "Answer", "text": "Often yes, but only after several approvals. A single-unit dwelling is a permitted use in the county's A-1, A-2, R-E and R-1 districts, subject to lot size, setback and district conditions. The Health Department must approve the septic and well plans, the highway authority must approve the driveway, and the county building permit follows. The Health Department's page says a building permit cannot be issued without proper zoning, so confirm the zoning first."}}, {"@type": "Question", "name": "How many acres do I need for a house in rural Boone County?", "acceptedAnswer": {"@type": "Answer", "text": "It depends on the district. Under the posted ordinance, a non-agricultural lot in A-1 needs at least 5 acres. In A-2, a residential lot must be between 2 and 5 acres. R-E requires 2 acres, and R-1 requires 1 acre without sewer and water or 9,000 square feet with them. Older lots of record may be built under earlier rules. Ask the Planning Department which version of the ordinance governs your parcel."}}, {"@type": "Question", "name": "Who approves a well and septic system in Boone County?", "acceptedAnswer": {"@type": "Answer", "text": "The Boone County Health Department. A well needs a permit before it is built, sealed, deepened or modified, and a new well must be tested before the water is used. A septic system needs soil borings from a certified classifier, a scaled plan, a permit and an inspection before anything is covered. The installer must hold Illinois and Boone County licenses. Call Environmental Health at 815-544-2951, extension 2."}}, {"@type": "Question", "name": "Do I need a well and septic inspection when I buy an acreage home?", "acceptedAnswer": {"@type": "Answer", "text": "The Health Department does not require one for a sale, but your lender or your contract may, and the department calls it a good idea to prevent unexpected repair costs. You request an evaluation with its Real Estate Inspection Request form or by calling 815-544-2951, extension 2. The seller's disclosure covers only what the seller knows, so the inspection is how you find the rest."}}, {"@type": "Question", "name": "How is farmland assessed for property tax in Illinois?", "acceptedAnswer": {"@type": "Answer", "text": "Under state law, cropland is assessed by its soil productivity index, adjusted for slope, drainage, flooding and field shape. Permanent pasture is assessed at one-third of the cropland value, and other farmland at one-sixth. The farm dwelling and the tract it sits on are assessed at one-third of fair cash value. Land primarily used for residential purposes does not qualify as a farm, and a parcel generally must have been farmed for two preceding years."}}, {"@type": "Question", "name": "Do I need a permit to put a driveway on a rural road in Boone County?", "acceptedAnswer": {"@type": "Answer", "text": "Yes. Because a driveway places pavement on public right-of-way, the county says the law requires approval from the appropriate highway authority before you install it. That is the agency that maintains your road, which may be a township, the county or the state. Ask the Boone County Highway Department which authority covers your road, and apply before you begin any work."}}, {"@type": "Question", "name": "How do I know if a property is in the city or in the county?", "acceptedAnswer": {"@type": "Answer", "text": "Check the zoning and permitting jurisdiction before anything else. The county's building page warns that if its online system rejects an address, the property may not be in its jurisdiction. You can also ask the city's planning department at 815-547-7177 and the county's Planning Department. A property can also be annexed later, as two subdivisions north of US Business Route 20 were in August 2025."}} ...