Guide

Stage 1: Confirm your property's wastewater path

Before planning a cesspool conversion, confirm whether the property is connected to a municipal sewer or uses an onsite wastewater system. The Hawaiʻi Department of Health administers onsite wastewater systems, but its wastewater jurisdiction does not extend to properties already served by municipal sewer.

Start with your water bill. A sewer charge may indicate that the property has sewer service. If the bill does not settle the question, contact the relevant county department to confirm the property's status. A DOH notice, an earlier wastewater approval, or another property record may also be useful if you already have it, but there is no verified universal document checklist for this first stage.

There is no official duration for confirming a parcel's wastewater status. Some properties may require county confirmation, so avoid treating this step as an instant check or promising a fixed timeline.

If the property is not sewer-served, the next planning step is to gather the basic property facts you will use when approaching an engineer. This transition is part of this Guide's homeowner journey, not an official DOH stage boundary.

If your process began with an agency notice, read What to Do After a DOH Cesspool Letter for related orientation. The article is a companion resource, not the factual source for this stage.

Stage 2 — Assemble property facts and project goals

Before you contact an engineer, gather the property information you already have and write down what you want the project to accomplish. A useful starting set may include:

• the property address and tax map key (TMK);
• the dwelling and bedroom count;
• the known or suspected cesspool location;
• prior plans, drawings, wastewater approvals, or other property records; and
• your goals for the property, including any changes you are considering.

This is a preparation list, not an official checklist. The exact information an engineer needs can depend on the property and the proposed work. If an item is missing or uncertain, note that rather than treating it as a reason to stop. The engineer may ask follow-up questions after reviewing what is available.

Gathering these facts does not begin engineering or design work by itself. The engineer’s responsibilities and the terms of the engagement begin when you hire the engineer under the agreed scope.

Your next step

Use the information you assembled to contact a Hawaiʻi-licensed civil engineer, then verify the engineer’s license before hiring them. The next stage explains that step.

For context on how this preparation fits into the larger process, see How long does a cesspool conversion take?.

Stage 3 — Hire and verify a Hawaiʻi-licensed civil engineer

The first professional to hire for an individual wastewater system (IWS) project is a Hawaiʻi-licensed civil engineer. The engineer will evaluate your property and prepare the IWS design and application in the stages that follow.

Before hiring an engineer, use the Department of Commerce and Consumer Affairs (DCCA) Professional and Vocational Licensing Search to verify that the engineer holds a Hawaiʻi civil engineer license. Save or print the search result for your project records.

When comparing engineers, you may also want to review the proposed scope, fee, and engagement terms. These private documents can help define the working relationship, but they are not presented here as official DOH forms or as a universal contract checklist.

No official selection timeline or availability benchmark applies to every project. Ask each engineer about their availability and next steps rather than relying on a standard estimate.

Your next step

After you hire and verify the engineer, schedule the engineer’s evaluation of the property. The next stage explains what happens during that evaluation.

For context on how engineering and design fit into the overall project cost, see How much does a cesspool conversion cost?. Specific price ranges depend on the property and remain outside this stage.

Stage 4 — Engineer evaluates site conditions

Your engineer evaluates the property so they can design an individual wastewater system that meets state requirements. You provide access to the site and share the property information you have available.

What happens during this stage

The engineer gathers and verifies the site information needed for the design. That work may include field observations, measurements, and other parcel-specific information. The exact assessment record depends on the property; the approved sources do not establish one universal set of field notes or supporting documents for every site.

Soil, elevation, survey, or water-feature information may be relevant on some parcels. Ask your engineer what is needed for your property rather than treating any general list as a requirement.

What you can do

• Coordinate site access with your engineer.
• Share available property information that may help the evaluation.
• Ask whether the engineer needs any additional parcel-specific information before design work proceeds.

There is no source-approved universal homeowner checklist for this stage.

What can affect timing

Additional field investigation or missing access may extend the evaluation. No official duration or universal trigger for added investigation was identified, so use your engineer’s project-specific guidance instead of a general timeline estimate.

What comes next

After the site information has been verified, the engineer uses it to prepare the IWS design and application package for the Hawaiʻi Department of Health.

Related reading

What does cesspool conversion cost? explains the main project cost categories. Site conditions can affect project scope, but specific cost effects or amounts require property-specific evaluation and are not estimated here.

Stage 5 — Engineer prepares the IWS design/application

Your engineer uses the verified site information to design the individual wastewater system and prepare the application material for the Hawaiʻi Department of Health. You provide owner information and complete any owner portions the engineer identifies for the current application package.

What happens during this stage

The engineer develops the IWS design and assembles the DOH application package. This is preparation, not agency review or approval. DOH review begins only after the completed package is submitted in the next stage.

The approved sources verify the design and application package at a general level, but they do not establish an exact checklist, current form revision, attachment list, fee schedule, or owner signature point for this draft. Ask your engineer which current materials and owner actions apply to your project.

What you can do

• Provide owner and property information requested by your engineer.
• Review and complete any owner portions the engineer identifies.
• Ask your engineer whether any information or authorization is still needed before submission.

There is no source-approved universal owner checklist for this stage.

What can affect timing

No official duration for design and application preparation was identified. The approved source map does not establish universal timing effects from property complexity, survey work, or missing information, so use your engineer’s project-specific guidance instead of a general estimate.

What comes next

After the design and application package is complete, the engineer submits it to DOH. Agency review has not occurred yet.

Related reading

How long does cesspool conversion take? places design preparation before agency review without assigning a site-specific duration.

Stage 6 — Engineer submits the design/application to DOH

Your engineer submits the completed individual wastewater system design and application package to the Hawaiʻi Department of Health. If the engineer identifies outstanding owner information or authorization, provide it through the engineer so the submission can move forward.

What happens during this stage

The engineer sends the IWS design and application package to DOH. DOH receives the package for design review, but the review itself—and any questions or revision requests—belongs to the next stage.

The approved sources verify the submitted package at a general level. They do not establish a required receipt or tracking format, or exact submission-time owner requirements, for this draft. Ask your engineer how the submission will be documented and whether any owner action remains.

What you can do

• Confirm with your engineer that the package has been submitted.
• Provide any outstanding information or authorization requested through your engineer.
• Ask your engineer how they will share DOH questions, revision requests, or status updates with you.

There is no source-approved universal owner checklist or required submission-tracking format for this stage.

What can affect timing

No official duration for submission or intake/completeness screening was identified. A historical DOH review average belongs to the later review stage and is not a Stage 6 estimate. Use your engineer’s project-specific guidance rather than assuming a submission or intake timeline.

What comes next

After submission, await DOH review. Route technical questions or revision requests through your engineer. Review and any resulting comments are part of Stage 7, not this stage.

Related reading

What to do after receiving a DOH cesspool letter explains the difference between an agency notice and the engineer-led design-submittal process. This editorial link does not establish a Stage 6 requirement.

Stage 7: DOH reviews the submitted design/application

After your engineer submits the IWS design and application, the Hawaiʻi Department of Health (DOH) reviews the package in first-come, first-served order to determine whether the design complies with applicable rules.

Your engineer is DOH’s primary contact for technical questions and reviewer comments. As the homeowner, expect progress updates and any requests for information or action to come through your engineer rather than trying to resolve engineering comments directly with DOH.

What is reviewed

DOH reviews the submitted IWS design/application package. If the reviewer needs clarification or changes, comments may be sent to the engineer. There is no single universal format established for those comments, so rely on your engineer to explain what was requested and whether you need to provide anything.

How long review may take

DOH reports a historical average of about 10 days to complete reviews. That average includes weekends, holidays, queue and staffing conditions, and out-of-office days. It is not a deadline, guarantee, or estimate for your property: the scope and complexity of a project and other circumstances can make review shorter or longer.

What happens next

• If DOH issues comments, your engineer addresses them and resubmits the needed material in Stage 8.
• If the design complies with the rules, DOH issues approval to construct.

For more context on why a historical average is different from a project-specific schedule, see How Long Does Cesspool Conversion Take?.

Stage 8 — Your engineer resolves comments and DOH issues approval to construct

If the Hawaiʻi Department of Health (DOH) sends review comments, your civil engineer responds and revises the design or application materials as needed. DOH then reviews the response. When the design complies with DOH rules, DOH issues approval to construct.

Who does what

• Your engineer: Addresses DOH’s reviewer comments and submits the response and any needed revisions.
• DOH: Reviews the engineer’s response and issues approval to construct when the design complies with its rules.
• You: Complete any task your engineer routes to you. There is no single, verified homeowner task list for this stage, so ask your engineer what is needed for your project.

Documents and milestone

The working materials may include the engineer’s response and revised design or application materials. The exact resubmittal set depends on the comments and is not established as one universal checklist.

The key milestone is DOH’s approval to construct. Keep that approval with your project records and use it to move into contractor selection and construction preparation.

Timing note

DOH reports that submitting engineers have taken about 25 days on average to respond to and address Wastewater Branch comments. That is a historical average, not a deadline, guarantee, or estimate for your project. The reviewed DOH material does not state a separate average for DOH’s re-review after the engineer responds.

Before you move on

• Confirm with your engineer that all reviewer comments have been addressed.
• Confirm that DOH has issued approval to construct.
• After approval, begin hiring and verifying the appropriately licensed contractor or contractors for the work.

For more context on review and response timing, see How Long Does Cesspool Conversion Take?. The article is a related explanation, not the factual source for this stage.

Stage 9 — Hire the licensed contractor and prepare for construction

Once DOH has approved the design for construction, hire a properly licensed contractor to install the approved individual wastewater system (IWS). Use the Hawaiʻi Department of Commerce and Consumer Affairs (DCCA) license-search tool to verify the contractor’s license class and current status before work begins.

What to do

• Confirm that you have DOH approval to construct before moving into construction preparation.
• Verify that the contractor holds an applicable A, C-9, C-37, C-37a, or C-43 license.
• Ask the contractor and engineer whether the project scope also requires a licensed plumber or electrician.
• Give the contractor the approved design and coordinate with the licensed civil engineer who will monitor construction.
• Contact the local county building department about the status of any building permit that may apply to the project. County permitting roles and requirements can vary, so do not assume there is one checklist or filing process for every property.

Keep available

Keep the DOH approval to construct and the DCCA contractor-license record with the project files. A contractor proposal, construction agreement, schedule, or county permit package may also be useful for managing the work, but the approved sources do not establish one universal required set or standard contract terms for every project.

Timing

No official duration has been identified for contractor selection, contracting, mobilization, or county permitting. Ask the contractor and engineer for project-specific scheduling information rather than relying on a universal estimate.

Next step

When the contractor has the approved design and construction is ready to begin, continue to Stage 10: construction of the IWS under monitoring by the licensed civil engineer.

For help understanding which costs may belong to construction rather than engineering or agency review, see What Does Cesspool Conversion Cost?. Specific costs depend on the project; this stage does not provide a universal price range.

Stage 10 — Contractor constructs the IWS under engineer monitoring

With approval to construct in place, the contractor builds the individual wastewater system (IWS) according to the approved design. The licensed civil engineer monitors construction.

Your role as the homeowner is to provide access to the property. Ask your engineer or contractor what they need from you for your specific project; the approved sources do not establish one universal homeowner construction checklist.

Keep the approved work on track

The approved design and DOH approval to construct guide this stage. At the end of construction, the engineer and contractor will need to prepare the IWS Construction Inspection Report and Contractor Certification Form for the next stage.

Project teams may also use items such as logs, photographs, change orders, or component records. However, the approved sources do not establish those items as a universal required set. Follow the directions of your engineer and contractor for your project.

The exact method, timing, and documentation for closing the old cesspool are not established in the approved material for this draft. Confirm project-specific requirements with your engineer rather than relying on a general checklist.

How long can construction take?

DOH reports that construction or installation of a new IWS has taken about 200 days on average in its internal records. This is a historical average—not a guaranteed active-construction period or an estimate for your property.

The approved sources do not quantify how weather, deliveries, site access, or contractor availability may affect an individual schedule. Get current, project-specific scheduling information from your contractor and engineer.

Next step

When construction is complete, the engineer and contractor prepare the final inspection and contractor-certification records for submission in Stage 11.

Related reading: What Does Cesspool Conversion Cost in Hawaiʻi? explains the major cost categories. Site-specific prices or cost effects are not established in this stage draft.

Stage 11 — Engineer submits final construction documentation

Physical construction may be complete, but final documentation is still a separate project step. At the end of construction, the licensed civil engineer submits the completed IWS Construction Inspection Report to the Hawaiʻi Department of Health Wastewater Branch. The contractor completes the Contractor Certification Form, which the engineer submits with the inspection report.

Who does what

• Engineer: Completes and submits the IWS Construction Inspection Report together with the completed Contractor Certification Form.
• Contractor: Completes the Contractor Certification Form for the final package.
• Homeowner: Stay in contact with the engineer about the package’s status. The approved sources do not assign the homeowner a submission role or establish a universal homeowner record-retention checklist for this stage.

Documents for this stage

The verified final documents are:

• the completed IWS Construction Inspection Report; and
• the completed Contractor Certification Form.

The approved sources do not establish as-built drawings or a separate maintenance package as universal Stage 11 submission requirements.

Timing and possible delay

No official duration was identified for preparing or submitting the final forms. DOH says approval to use can be significantly delayed when final reports and forms do not demonstrate that construction and installation followed the approved design. That warning does not provide a specific delay estimate.

What happens next

After the engineer submits both completed forms, the Wastewater Branch reviews them. If there are no discrepancies, the process can move to DOH’s approval-to-use step.

For the broader sequence, see How Long Does a Cesspool Conversion Take?. The timeline article provides context; the verified Stage 11 requirements above come from the approved internal source map.

Stage 12 — DOH issues approval to use

Once the final construction paperwork has been submitted, the Hawaiʻi Department of Health (DOH) Wastewater Branch reviews the completed IWS Construction Inspection Report and Contractor Certification Form. If there are no discrepancies, DOH issues the approval-to-use letter to the engineer.

Who does what

• DOH Wastewater Branch: Reviews the two required final forms and issues the approval-to-use letter when there are no discrepancies.
• Engineer: Receives the approval-to-use letter from DOH.
• Homeowner: Obtain a copy of the final approval and keep it with the property records. The approved sources do not establish a universal delivery method, retention period, or complete recordkeeping list for homeowners.

Document to keep

The key document at this stage is the DOH approval-to-use letter. Operating, pumping, inspection, and maintenance instructions can vary by system; the approved sources do not establish one universal final maintenance package.

What can delay this stage

DOH cannot issue final approval to use unless the engineer has submitted both the completed IWS Construction Inspection Report and the completed Contractor Certification Form. Discrepancies in those forms must be resolved before the letter can be issued. The approved sources do not provide an official final-review or letter-issuance timeframe.

Your next step

The approval-to-use letter marks the end of this 12-stage conversion journey. Keep the approval with the property records and follow the operating and maintenance requirements that apply to the installed system.

Related reading: What a DOH cesspool letter means explains how an initial DOH notice differs from the final approval-to-use letter.