What should Chino Preserve buyers know about the soils report on former dairy land?

You are considering a home in The Preserve, and the property’s former use raises a practical question: what did the city require before homes could be built there?

The answer is that the City of Chino’s environmental documents require a soils report for grading on former dairy lands and other agricultural properties within the plan area’s scope. That report must address organic material and methane potential. This requirement does not mean a particular home has either problem.

This is general information and not legal advice.

What does the soils report requirement mean for a buyer?

The requirement means the development’s grading work should have followed a city-approved soils engineer’s recommendations before and during construction.

The controlling language appears in mitigation measure GS-3 of The Preserve Master Plan Environmental Impact Report. In the Mitigation Monitoring Program, the measure is titled “Soils Report - Dairy Lands.”

For a buyer, the report is a document to ask about. It is not a finding that every lot contains manure or has methane accumulation. The EIR requires the soils engineer to examine those subjects and identify measures when the report finds they are needed.

The measure concerns development and grading. The source documents say nothing about duties for resale homeowners.

Why does The Preserve have a dairy lands rule?

The rule exists because The Preserve includes former and existing farm and dairy property, and the EIR identified remaining organic residue as a development concern.

The city’s Preserve page describes an area of approximately 5,435 acres south of Kimball Avenue, north of State Route 71, west of Hellman Avenue and east of Euclid Avenue. The area was annexed to Chino in July 2003. Approximately half is planned for residential, commercial, industrial and airport-related development, while the other half remains open space for natural, recreational and agricultural uses.

The EIR identifies a specific soils question: “Of special concern in the plan area is the definition of the distribution, character and thickness of surface organic residue (e.g. manure and other organic deposition) within the soils that remain from activities of the dairy industry.”

That language describes what development investigations need to examine. It does not say all of Chino is former dairy land, and it does not establish conditions at an individual home. Buyers comparing this issue across city boundaries can also read the guide to former dairy land homes in Eastvale, while keeping in mind that the governing documents are different.

What does mitigation measure GS-3 require?

GS-3 requires an approved soils engineer to direct the handling of organic material and address methane potential in the soils report.

The measure states: “Grading operations on all former dairy lands and other agricultural properties will be conducted in accordance with the soils report prepared by a registered soils engineer approved by the City of Chino.” That engineer makes recommendations about removing organic material or handling it during grading.

GS-3 also says all manure from dairy corrals and other surface areas shall be stripped and removed before grading, in accordance with applicable codes and regulations. Methane potential must be addressed in the soils report for former dairy lands and other agricultural properties.

If the report identifies potential for methane accumulation or release, soils testing must occur. The test results and remedial measures must then be identified in the report. The EIR does not provide a methane reading for a particular tract or a health finding.

Who checks the report, and when?

The City Engineer and soils engineer are responsible for verification before the grading permit and during construction.

The Mitigation Monitoring Program gives the verification method as “Plan Check and Monitoring of construction.” Its stated timing is “Prior to Issuance of Grading Permit and During Construction.” The City Engineer’s office is the office the monitoring program names, and a buyer can ask it who holds the approved report.

The EIR also says building code requirements, grading code requirements and engineering investigation report requirements are safeguards against unsafe design and construction practices involving soil stability and potentially unsuitable foundation conditions.

It is not verified whether the city has since amended GS-3. Because the posted EIR draws on a Wilson Geosciences Inc. report from 2000, ask the city which current conditions of approval govern the specific tract rather than treating the original EIR language as the entire present record.

What other soil conditions do the city documents address?

The city documents also require project-level study of geologic and soil conditions beyond former dairy use.

Mitigation measure GS-1 says: “All applications for individual development projects shall include a detailed Geotechnical and Soils Engineering Study which addresses potential hazards associated with fault rupture, seismicity and groundshaking, liquefaction, subsidence and near-surface groundwater.” The monitoring program places that review before the grading permit and identifies the City Engineer as the responsible party.

GS-2 says individual developments “shall be constructed according to requirements established in geologic studies pertaining to the project site.” Its monitoring entry calls for plan check by the Building Official.

The EIR says the plan area is entirely underlain by Pleistocene and Holocene, or Recent, alluvium. It describes plan-area soils as generally susceptible to expansion, settlement and possibly hydroconsolidation. Groundwater in the Chino Basin is described at depths of about 100 feet in the plan area’s northeast corner and possibly less than 30 feet in southern portions. The document says investigations should determine whether shallow groundwater is present at a given site.

For subsidence, the EIR says there was no specific plan-area information when it was prepared, while assuming significant potential throughout the plan area and recommending stepwise data evaluation. That historical statement should not be presented as a current finding for a home.

What should you ask before buying?

You should ask for the tract-specific soils record and the current conditions of approval that apply to the lot.

Useful questions include:

• Was this lot part of former dairy land or another agricultural property?
• Did the tract’s soils report address organic material and methane potential?
• Can the builder or seller provide a copy of the approved soils report?
• If they cannot provide it, who at the City Engineer’s office holds the approved report?
• Which conditions of approval does the City of Chino Development Services Planning counter show for this tract?
• Did the report identify testing or remedial measures, and where are those measures documented?

These are document questions, not assumptions about the property’s condition. If you are also reviewing a newly built home, the new construction buyer guide provides a broader checklist. For a parcel that has not yet been developed, the guide to checking land before buying can help organize the records to request.

We spoke with a Chino Preserve buyer who became concerned after learning that the homes were built on former dairy land. He wanted to know whether that history alone made the property unsafe. We reviewed the soils information with him because the useful questions involved what was tested, what was found and what measures were required, not simply the land’s former use.

How do you connect a home to the correct tract record?

You connect a home to the correct record by identifying its tract and asking the city which approvals and reports apply to it.

A City Council agenda from October 6, 2026 covered the Final Map and Subdivision Improvement Agreement for Tract Map No. 16420-8, including Block 8 and part of Block 6, bounded by Pine Avenue, Main Street, Legacy Park Street and West Preserve Loop. The item was approved according to the city’s meeting data, but it does not establish the contents of the tract’s soils report or a soil condition at any home.

The short version

The short version is that The Preserve EIR requires soils reports for grading on former dairy lands and other agricultural properties, with organic material and methane potential addressed.

GS-3 requires surface manure removal before grading and testing when methane accumulation or release potential is identified. The City Engineer and soils engineer verify compliance through plan check and construction monitoring.

This does not establish a condition at a particular house. Ask for the tract-specific report and confirm which current conditions of approval apply.

When you are ready to compare the property with local pricing information, use the home value tool.