Due diligence
Contamination checks
This stage screens past land uses, council-held records, visible evidence, hazardous substances, soil disturbance, disposal implications, specialist investigation needs, and planning or health controls. This page shows what a beginner residential developer in Auckland should check, who to ask, what evidence to save, and where to verify before committing money or instructions.
How to execute this stage
Micro-stage control plan
Work through each applicable step in order. A hold point means pause the dependent decision or work until the stated evidence and authorised review are complete.
01Past potentially contaminating activitiesLevel 2 · Due diligence
TaskCheckHold pointEvidenceRecordNext actionSimple explanation
Past potentially contaminating activities
Technical context
Test this point against LIM, the current feasibility version and written input from Suitably qualified environmental practitioner. Separate verified facts, professional opinion and assumptions.
Why it matters: This check can change yield, consent pathway, acquisition terms, funding, cost, programme or exit strategy. It must be resolved before the developer relies on whether specialist investigation is required.
Prerequisites
- LIM is current and its source/date are recorded.
- The project objective, feasibility version and decision deadline are clear.
- Suitably qualified environmental practitioner has a focused brief where professional confirmation is required.
Checks
- Does LIM directly support the conclusion?
- Which information is verified, assumed, missing, superseded or contradictory?
- Has the feasibility, programme, risk register and decision register been updated?
Evidence to save
- LIM
- Written Suitably qualified environmental practitioner response or a recorded reason it is not required
- Dated feasibility/risk/decision update
Hold point
Do not waive a condition, instruct design/work, commit funding, lodge, purchase, settle or represent the conclusion as confirmed until the authorised decision-maker has the required evidence and advice.
Stop or escalate when
- The source is missing, old, inconsistent or outside the reviewer's scope.
- The check changes yield, approval pathway, funding, legal rights, tax, safety or a material cost/programme assumption.
- A deadline is approaching and the responsible professional has not confirmed the position.
Documents and records
- LIM
- Environmental consultant brief
- Due diligence checklist
- Current feasibility, risk register and decision register
- Cost effect
- Record changes to land value, consultant/council cost, construction/civil cost, finance, holding cost, contingency and exit value before whether specialist investigation is required.
- Programme effect
- Record the decision deadline, dependencies, information lead time and effect on acquisition, consent, procurement, construction, sales or settlement milestones.
Next action
Imported fill
Applicability: Confirm whether this check applies to the actual site, ownership, strategy, consent pathway, infrastructure and delivery model; record a reason when not applicable.
Use current site-specific documents and appropriately appointed professional advice. BuildPath does not make the development decision for you.
02Imported fillLevel 2 · Due diligence
TaskCheckHold pointEvidenceRecordNext actionSimple explanation
Imported fill
Technical context
Test this point against Property file, the current feasibility version and written input from Planner. Separate verified facts, professional opinion and assumptions.
Why it matters: This check can change yield, consent pathway, acquisition terms, funding, cost, programme or exit strategy. It must be resolved before the developer relies on whether purchase conditions need extension.
Prerequisites
- Property file is current and its source/date are recorded.
- The project objective, feasibility version and decision deadline are clear.
- Planner has a focused brief where professional confirmation is required.
Checks
- Does Property file directly support the conclusion?
- Which information is verified, assumed, missing, superseded or contradictory?
- Has the feasibility, programme, risk register and decision register been updated?
Evidence to save
- Property file
- Written Planner response or a recorded reason it is not required
- Dated feasibility/risk/decision update
Hold point
Do not waive a condition, instruct design/work, commit funding, lodge, purchase, settle or represent the conclusion as confirmed until the authorised decision-maker has the required evidence and advice.
Stop or escalate when
- The source is missing, old, inconsistent or outside the reviewer's scope.
- The check changes yield, approval pathway, funding, legal rights, tax, safety or a material cost/programme assumption.
- A deadline is approaching and the responsible professional has not confirmed the position.
Documents and records
- Property file
- Environmental consultant brief
- Due diligence checklist
- Current feasibility, risk register and decision register
- Cost effect
- Record changes to land value, consultant/council cost, construction/civil cost, finance, holding cost, contingency and exit value before whether purchase conditions need extension.
- Programme effect
- Record the decision deadline, dependencies, information lead time and effect on acquisition, consent, procurement, construction, sales or settlement milestones.
Next action
Fuel or chemical storage
Applicability: Confirm whether this check applies to the actual site, ownership, strategy, consent pathway, infrastructure and delivery model; record a reason when not applicable.
Use current site-specific documents and appropriately appointed professional advice. BuildPath does not make the development decision for you.
03Fuel or chemical storageLevel 2 · Due diligence
TaskCheckHold pointEvidenceRecordNext actionSimple explanation
Fuel or chemical storage
Technical context
Test this point against Historic aerials or land-use information, the current feasibility version and written input from Geotechnical or civil engineer. Separate verified facts, professional opinion and assumptions.
Why it matters: This check can change yield, consent pathway, acquisition terms, funding, cost, programme or exit strategy. It must be resolved before the developer relies on remediation and disposal allowance.
Prerequisites
- Historic aerials or land-use information is current and its source/date are recorded.
- The project objective, feasibility version and decision deadline are clear.
- Geotechnical or civil engineer has a focused brief where professional confirmation is required.
Checks
- Does Historic aerials or land-use information directly support the conclusion?
- Which information is verified, assumed, missing, superseded or contradictory?
- Has the feasibility, programme, risk register and decision register been updated?
Evidence to save
- Historic aerials or land-use information
- Written Geotechnical or civil engineer response or a recorded reason it is not required
- Dated feasibility/risk/decision update
Hold point
Do not waive a condition, instruct design/work, commit funding, lodge, purchase, settle or represent the conclusion as confirmed until the authorised decision-maker has the required evidence and advice.
Stop or escalate when
- The source is missing, old, inconsistent or outside the reviewer's scope.
- The check changes yield, approval pathway, funding, legal rights, tax, safety or a material cost/programme assumption.
- A deadline is approaching and the responsible professional has not confirmed the position.
Documents and records
- Historic aerials or land-use information
- Environmental consultant brief
- Due diligence checklist
- Current feasibility, risk register and decision register
- Cost effect
- Record changes to land value, consultant/council cost, construction/civil cost, finance, holding cost, contingency and exit value before remediation and disposal allowance.
- Programme effect
- Record the decision deadline, dependencies, information lead time and effect on acquisition, consent, procurement, construction, sales or settlement milestones.
Next action
Horticultural or industrial history
Applicability: Confirm whether this check applies to the actual site, ownership, strategy, consent pathway, infrastructure and delivery model; record a reason when not applicable.
Use current site-specific documents and appropriately appointed professional advice. BuildPath does not make the development decision for you.
04Horticultural or industrial historyLevel 2 · Due diligence
TaskCheckHold pointEvidenceRecordNext actionSimple explanation
Horticultural or industrial history
Technical context
Test this point against GeoMaps layers, the current feasibility version and written input from Lawyer. Separate verified facts, professional opinion and assumptions.
Why it matters: This check can change yield, consent pathway, acquisition terms, funding, cost, programme or exit strategy. It must be resolved before the developer relies on whether the site remains viable.
Prerequisites
- GeoMaps layers is current and its source/date are recorded.
- The project objective, feasibility version and decision deadline are clear.
- Lawyer has a focused brief where professional confirmation is required.
Checks
- Does GeoMaps layers directly support the conclusion?
- Which information is verified, assumed, missing, superseded or contradictory?
- Has the feasibility, programme, risk register and decision register been updated?
Evidence to save
- GeoMaps layers
- Written Lawyer response or a recorded reason it is not required
- Dated feasibility/risk/decision update
Hold point
Do not waive a condition, instruct design/work, commit funding, lodge, purchase, settle or represent the conclusion as confirmed until the authorised decision-maker has the required evidence and advice.
Stop or escalate when
- The source is missing, old, inconsistent or outside the reviewer's scope.
- The check changes yield, approval pathway, funding, legal rights, tax, safety or a material cost/programme assumption.
- A deadline is approaching and the responsible professional has not confirmed the position.
Documents and records
- GeoMaps layers
- Environmental consultant brief
- Due diligence checklist
- Current feasibility, risk register and decision register
- Cost effect
- Record changes to land value, consultant/council cost, construction/civil cost, finance, holding cost, contingency and exit value before whether the site remains viable.
- Programme effect
- Record the decision deadline, dependencies, information lead time and effect on acquisition, consent, procurement, construction, sales or settlement milestones.
Next action
Visible staining or buried waste
Applicability: Confirm whether this check applies to the actual site, ownership, strategy, consent pathway, infrastructure and delivery model; record a reason when not applicable.
Use current site-specific documents and appropriately appointed professional advice. BuildPath does not make the development decision for you.
05Visible staining or buried wasteLevel 2 · Due diligence
TaskCheckHold pointEvidenceRecordNext actionSimple explanation
Visible staining or buried waste
Technical context
Test this point against Preliminary site investigation where required, the current feasibility version and written input from Auckland Council. Separate verified facts, professional opinion and assumptions.
Why it matters: This check can change yield, consent pathway, acquisition terms, funding, cost, programme or exit strategy. It must be resolved before the developer relies on whether specialist investigation is required.
Prerequisites
- Preliminary site investigation where required is current and its source/date are recorded.
- The project objective, feasibility version and decision deadline are clear.
- Auckland Council has a focused brief where professional confirmation is required.
Checks
- Does Preliminary site investigation where required directly support the conclusion?
- Which information is verified, assumed, missing, superseded or contradictory?
- Has the feasibility, programme, risk register and decision register been updated?
Evidence to save
- Preliminary site investigation where required
- Written Auckland Council response or a recorded reason it is not required
- Dated feasibility/risk/decision update
Hold point
Do not waive a condition, instruct design/work, commit funding, lodge, purchase, settle or represent the conclusion as confirmed until the authorised decision-maker has the required evidence and advice.
Stop or escalate when
- The source is missing, old, inconsistent or outside the reviewer's scope.
- The check changes yield, approval pathway, funding, legal rights, tax, safety or a material cost/programme assumption.
- A deadline is approaching and the responsible professional has not confirmed the position.
Documents and records
- Preliminary site investigation where required
- Environmental consultant brief
- Due diligence checklist
- Current feasibility, risk register and decision register
- Cost effect
- Record changes to land value, consultant/council cost, construction/civil cost, finance, holding cost, contingency and exit value before whether specialist investigation is required.
- Programme effect
- Record the decision deadline, dependencies, information lead time and effect on acquisition, consent, procurement, construction, sales or settlement milestones.
Next action
Soil disturbance and disposal pathway
Applicability: Confirm whether this check applies to the actual site, ownership, strategy, consent pathway, infrastructure and delivery model; record a reason when not applicable.
Use current site-specific documents and appropriately appointed professional advice. BuildPath does not make the development decision for you.
06Soil disturbance and disposal pathwayLevel 2 · Due diligence
TaskCheckHold pointEvidenceRecordNext actionSimple explanation
Soil disturbance and disposal pathway
Technical context
Test this point against Detailed site investigation or remediation plan where required, the current feasibility version and written input from Quantity surveyor. Separate verified facts, professional opinion and assumptions.
Why it matters: This check can change yield, consent pathway, acquisition terms, funding, cost, programme or exit strategy. It must be resolved before the developer relies on whether purchase conditions need extension.
Prerequisites
- Detailed site investigation or remediation plan where required is current and its source/date are recorded.
- The project objective, feasibility version and decision deadline are clear.
- Quantity surveyor has a focused brief where professional confirmation is required.
Checks
- Does Detailed site investigation or remediation plan where required directly support the conclusion?
- Which information is verified, assumed, missing, superseded or contradictory?
- Has the feasibility, programme, risk register and decision register been updated?
Evidence to save
- Detailed site investigation or remediation plan where required
- Written Quantity surveyor response or a recorded reason it is not required
- Dated feasibility/risk/decision update
Hold point
Do not waive a condition, instruct design/work, commit funding, lodge, purchase, settle or represent the conclusion as confirmed until the authorised decision-maker has the required evidence and advice.
Stop or escalate when
- The source is missing, old, inconsistent or outside the reviewer's scope.
- The check changes yield, approval pathway, funding, legal rights, tax, safety or a material cost/programme assumption.
- A deadline is approaching and the responsible professional has not confirmed the position.
Documents and records
- Detailed site investigation or remediation plan where required
- Environmental consultant brief
- Due diligence checklist
- Current feasibility, risk register and decision register
- Cost effect
- Record changes to land value, consultant/council cost, construction/civil cost, finance, holding cost, contingency and exit value before whether purchase conditions need extension.
- Programme effect
- Record the decision deadline, dependencies, information lead time and effect on acquisition, consent, procurement, construction, sales or settlement milestones.
Next action
Consent and remediation implications
Applicability: Confirm whether this check applies to the actual site, ownership, strategy, consent pathway, infrastructure and delivery model; record a reason when not applicable.
Use current site-specific documents and appropriately appointed professional advice. BuildPath does not make the development decision for you.
07Consent and remediation implicationsLevel 2 · Due diligence
TaskCheckHold pointEvidenceRecordNext actionSimple explanation
Consent and remediation implications
Technical context
Test this point against Disposal evidence, the current feasibility version and written input from Suitably qualified environmental practitioner. Separate verified facts, professional opinion and assumptions.
Why it matters: This check can change yield, consent pathway, acquisition terms, funding, cost, programme or exit strategy. It must be resolved before the developer relies on remediation and disposal allowance.
Prerequisites
- Disposal evidence is current and its source/date are recorded.
- The project objective, feasibility version and decision deadline are clear.
- Suitably qualified environmental practitioner has a focused brief where professional confirmation is required.
Checks
- Does Disposal evidence directly support the conclusion?
- Which information is verified, assumed, missing, superseded or contradictory?
- Has the feasibility, programme, risk register and decision register been updated?
Evidence to save
- Disposal evidence
- Written Suitably qualified environmental practitioner response or a recorded reason it is not required
- Dated feasibility/risk/decision update
Hold point
Do not waive a condition, instruct design/work, commit funding, lodge, purchase, settle or represent the conclusion as confirmed until the authorised decision-maker has the required evidence and advice.
Stop or escalate when
- The source is missing, old, inconsistent or outside the reviewer's scope.
- The check changes yield, approval pathway, funding, legal rights, tax, safety or a material cost/programme assumption.
- A deadline is approaching and the responsible professional has not confirmed the position.
Documents and records
- Disposal evidence
- Environmental consultant brief
- Due diligence checklist
- Current feasibility, risk register and decision register
- Cost effect
- Record changes to land value, consultant/council cost, construction/civil cost, finance, holding cost, contingency and exit value before remediation and disposal allowance.
- Programme effect
- Record the decision deadline, dependencies, information lead time and effect on acquisition, consent, procurement, construction, sales or settlement milestones.
Next action
Make and record the stage decision: Remediation and disposal allowance. Then open the next applicable development stage.
Applicability: Confirm whether this check applies to the actual site, ownership, strategy, consent pathway, infrastructure and delivery model; record a reason when not applicable.
Use current site-specific documents and appropriately appointed professional advice. BuildPath does not make the development decision for you.
Developer go / no-go control
Decision gates before the next commitment
A gate records whether evidence supports a commercial decision. It does not replace advice or predict an authority, lender, purchaser or market outcome.
Before the next material commitment
Decision: Proceed, pause, obtain evidence, or escalate
Minimum evidence
- • Current source documents and professional responses
- • Versioned feasibility, risk and programme update
- • Named owner and deadline for every unresolved dependency
Update before deciding
- • Cost and contingency
- • Time and holding/finance effect
- • Yield, value, consent and exit effect
Stop / escalate when
- • A material conclusion is still an assumption
- • Sources conflict or are out of date
- • The authorised decision-maker cannot see the downside consequence
What this stage means
- Contamination checks is the part of the project where the developer turns an idea into a checked decision, not a guess.
- The stage should connect market demand, planning rules, legal constraints, design, cost, funding, time, risk, and exit strategy.
- For Auckland residential development, the answer is site-specific. The same idea can be low risk on one site and unworkable on the next because of zoning, overlays, title interests, services, slope, flooding, neighbours, or finance.
Why this stage matters
- Early mistakes become expensive because land, design, consultants, holding costs, consent fees, and finance costs continue even when the project is paused.
- The developer needs written evidence for lenders, consultants, lawyers, valuers, builders, purchasers, and future dispute protection.
- This stage usually needs verification from Auckland Council LIM report, Auckland Council property file, Auckland Unitary Plan, Relevant professional advice before the developer treats the conclusion as reliable.
Step-by-step guide
- 1Define the decision needed at the end of this stage and the date it is needed by.
- 2Gather the stage documents: LIM, Property file, Historic aerials or land-use information, GeoMaps layers, and the remaining stage records.
- 3Read the documents once for understanding, then again to list unknowns, risks, contradictions, missing evidence, and professional questions.
- 4Ask the responsible professionals to confirm the critical points: Suitably qualified environmental practitioner, Planner, Geotechnical or civil engineer, Lawyer.
- 5Update the feasibility, programme, risk register, and decision register with source references and dates.
- 6Decide whether to proceed, pause, redesign, renegotiate, add conditions, seek more advice, or abandon the option.
- 7Save the evidence in a dated folder and write a short stage closeout note explaining what was decided and why.
What the developer must do
- Write down the development objective for contamination checks in one clear paragraph: build-to-sell, build-to-rent, retain one dwelling, subdivide, renovate, or staged development.
- Open the current feasibility, programme, decision register, risk register, and due diligence folder before making new commitments.
- Collect the documents needed for this stage: LIM, Property file, Historic aerials or land-use information, GeoMaps layers, Preliminary site investigation where required, Detailed site investigation or remediation plan where required, Disposal evidence.
- Send focused questions to the right people: Suitably qualified environmental practitioner, Planner, Geotechnical or civil engineer, Lawyer, Auckland Council, Quantity surveyor.
- Record assumptions separately from verified facts so the feasibility does not look more certain than it really is.
- Update cost, time, consent, finance, and sales assumptions immediately after receiving new information.
- Escalate anything that changes yield, sale price, cost, timing, consent pathway, title, funding, or settlement risk.
Verification
Source / where to check
Use current official information and the controlled documents for the actual project.
Use the LIM to check council-held information relevant to the land. Treat it as one due diligence document, not a substitute for title, survey, planning, engineering, legal, or finance advice.
Review historic building consents, drainage plans, previous approvals, CCC records where available, and historic plans. Compare records with what physically exists on site.
Check the operative plan, maps, zones, precincts, overlays, activity status, development controls, subdivision rules, and assessment criteria for the specific site.
Planner, surveyor, architect, engineer, quantity surveyor, lawyer, accountant, lender, valuer, real estate agent, and other project specialists must confirm site-specific decisions.
Project-specific consented documents and professional advice override generic guidance.
Common mistakes
- Treating an agent comment, generic online rule, or old document as verified site-specific advice.
- Forgetting to update the feasibility after design, consent, finance, or market information changes.
- Not allowing enough contingency, professional fees, council fees, finance costs, holding costs, and time risk.
- Failing to keep written records of who confirmed what and when.
- Using contamination checks to push ahead even when the red flags show the project should pause.
Common risks
- Yield reduces after proper planning, engineering, title, or infrastructure review.
- Costs increase after QS, builder, civil, geotechnical, demolition, asbestos, or consent information is received.
- Programme moves out because consultant inputs, council RFIs, neighbour issues, finance, title, or construction sequencing take longer than assumed.
- Funding or sales assumptions change before the project reaches settlement.
- The developer relies on unverified information and loses negotiating power or misses a due diligence deadline.
Common costs
- Professional fees for planner, architect/designer, surveyor, engineer, QS, lawyer, accountant, valuer, and lender reports.
- Council fees, consent fees, development contribution estimates, engineering approvals, infrastructure checks, and inspection/monitoring costs where relevant.
- Design revisions, reports, investigations, demolition/asbestos work, service location, geotechnical testing, and valuation updates.
- Holding costs such as interest, rates, insurance, utilities, temporary maintenance, and security.
- Contingency for unverified conditions until the relevant professional confirms them.
Quotes and fee proposals to obtain
- Obtain written fee proposals or quotations from the relevant stage professionals: Suitably qualified environmental practitioner, Planner, Geotechnical or civil engineer, Lawyer, Auckland Council, Quantity surveyor.
- Issue the same current documents and a clear scope to each party so prices, exclusions, assumptions, deliverables, lead times, and programme can be compared.
- Identify council, authority, investigation, testing, design, construction, monitoring, and close-out charges that may sit outside a consultant or contractor quote.
- Record every provisional sum, estimate, exclusion, expiry date, dependency, and unverified allowance in the Quote Register and feasibility.
- Do not approve an appointment or purchase order until scope ownership, evidence required, payment terms, variation process, insurance or competency checks, and completion deliverables are understood.
Common delays
- Waiting for property file, LIM, title instruments, survey information, consultant reports, or council responses.
- Design changes caused by planning controls, infrastructure constraints, engineering findings, budget pressure, or market feedback.
- Lender, valuer, lawyer, or purchaser conditions not being satisfied on time.
- Council RFI responses needing more consultant work than expected.
- Construction or subdivision closeout documents not matching settlement or sales deadlines.
Common consultant questions
- For Contamination checks, what are the three highest risks that could change cost, time, yield, or approval pathway?
- Which parts of your advice are confirmed, which are assumptions, and which require another professional to confirm?
- What documents did you rely on, and are any documents missing, outdated, superseded, or inconsistent?
- What decision does the developer need to make now, and what should wait until more information is available?
- What wording should go into the decision register, consultant meeting minutes, or lender/client update?
Red flags
- A professional says the issue is outside their scope and no one else has been asked to confirm it.
- The feasibility only works if optimistic sale prices, low construction costs, fast consent, low interest, and no delays all happen together.
- A title, planning, flooding, geotechnical, access, service, or covenant issue may prevent the intended yield.
- A seller, agent, builder, or consultant pressures the developer to waive due diligence before core checks are complete.
- The project file has no written evidence for a major decision.
When to stop and get professional advice
- Stop and get professional advice when title, easements, covenants, unit title, cross lease, or subdivision matters affect the proposal.
- Stop and get professional advice when zoning, overlays, activity status, notification, infrastructure capacity, flooding, geotechnical, contamination, or heritage could affect yield.
- Stop and get professional advice when GST, income tax, entity structure, lending, guarantees, or sale contract terms affect the decision.
- Stop and get professional advice when the developer is about to sign, waive a condition, lodge consent, start work, approve a variation, accept practical completion, or settle.
Decisions that must be made
- Whether specialist investigation is required
- Whether purchase conditions need extension
- Remediation and disposal allowance
- Whether the site remains viable
Evidence to save
- Dated source documents and consultant advice.
- Feasibility version showing the assumptions used at the time of decision.
- Risk register and decision register entries.
- Meeting notes, emails, marked-up plans, calculations, photos, and council/lender/consultant responses.
- Clear note of who approved the next step and any conditions attached to that approval.
Beginner-friendly example
Historic land use raises a possible contamination concern, so the developer obtains specialist advice rather than treating a clean-looking surface as proof.
Use this in my project
Turn contamination checks into controlled action
Open the relevant workspace register, create the project-specific record, link the controlling documents and preserve evidence. The guide does not automatically approve or verify the action.