What does this Korea septic-tank cleaning calculator plan?
This calculator combines a cleaning calendar, a local fee formula, and Korea’s capacity-based fine reference in one planning view.
Enter the last documented cleaning date and a cycle confirmed for the facility to estimate the next planned date and the number of calendar days remaining or overdue.
Enter the base fee, included volume, excess unit, unit fee, additional fixed fee, and special-work surcharge from a local tariff or provider quote to estimate regular and special-work cost.
The result also converts the regular estimate into an average annual budget, monthly reserve, and three-year budget.
The tool is for private sewage-treatment facilities in South Korea, including septic tanks and sewage-treatment facilities attached to homes, small commercial properties, lodging, and rural facilities.
It does not determine whether a facility is lawful, whether a six-month exception applies, whether cleaning is technically sufficient, whether a violation has occurred, or what fine an authority will assess.
Use it to prepare a calendar and cash note before confirming the applicable cycle, current tariff, and booking with the competent city, county, or district office and a registered cleaning provider.
Schedule control
Turn a documented cleaning date and confirmed interval into a next-date reminder.
Local fee arithmetic
Apply the locality’s included volume, excess-unit method, surcharge, and truncation rule.
Fine reference
Read the Annex 8 size and violation-count amount without treating it as an assessment.
Korea’s annual rule and the limited six-month rule
The legal sources and local fee examples on this page were checked on August 16, 2026.
Under Enforcement Rule of the Sewerage Act Article 33, the general septic-tank requirement is internal cleaning at least once a year.
A six-month requirement can apply to specified tourism accommodation, specified tourist-use facilities, specified food-service businesses, and lodging businesses located in specified areas under Enforcement Decree Article 4.
The area tests and business exclusions matter together, so a pension, restaurant, or lodging label by itself is not enough to choose six months.
A sewage-treatment facility needs a separate confirmation
Article 33 requires a sewage-treatment facility to be cleaned as necessary to preserve normal function by removing settled sludge and floating material.
It also states an annual requirement for a facility installed in an area that sends sewage to a public sewage-treatment or public wastewater-treatment facility.
The calculator cannot inspect the discharge connection, condition, or operating need, so use a cycle confirmed from the completion record, local notice, inspection, or competent authority.
A mayor, county head, or district head may extend the cleaning period for a closed facility, an entirely unused building, or another unavoidable reason under the Rule.
Non-use does not create an automatic extension.
Keep the approval and its revised date, then enter that confirmed interval through the custom-cycle option.
How to use the calculator
- Identify the facility and its legal size field
For a septic tank, use the design population shown on the facility plate or completion record.
For a sewage-treatment facility, use the rated daily capacity in cubic metres per day.
- Find the last completed cleaning date
Use a cleaning certificate, receipt, local notice, or property management record rather than an estimated date.
Leave the date blank while you retrieve the record if it is unknown.
- Choose a supported cycle basis
Select the general annual septic-tank rule, a six-month rule whose eligibility has been confirmed, or a month interval stated in a notice or approval.
- Copy the local fee structure
Enter the cleaning volume, base included volume, base fee, excess volume unit, unit fee, and pro-rata or rounded-up billing method exactly as documented.
- Add only confirmed work conditions
Separate a percentage surcharge for night or underground work from a fixed charge for access, hose length, or another item stated in writing.
- Turn the result into an action
Create a reminder 30 days before the planned date, reserve the monthly amount, and request a current written quote.
Treat the fine amount as a legal-table reference and confirm any actual compliance question with the authority.
Fee formula and the Gwangjin 5 m³ worked example
Excess volume equals cleaning volume minus the volume included in the base fee, with a minimum of zero.
Divide the excess volume by the tariff’s unit volume, preserving the fraction for pro-rata billing or rounding a positive remainder up for unit billing.
Multiply billed units by the excess-unit fee, add the base fee and any fixed additional fee, then apply the selected truncation unit.
The special-work result applies the surcharge to base plus excess fee before adding the separate fixed fee.
Gwangjin-gu’s official guide states a KRW 24,500 base fee for 0.75 m³, KRW 2,350 for each extra 0.1 m³, and a 7% premium for night or underground work.
At 5 m³, the excess is 4.25 m³ and the pro-rata unit count is 42.5.
This is a locality-specific official example, not a default tariff for Seoul or Korea.
Gwangjin-gu five cubic metre cleaning-fee example| Calculation item | Value | Arithmetic |
|---|
| Excess volume | 4.25 m³ | 5 − 0.75 |
| Excess fee | KRW 99,875 | 4.25 ÷ 0.1 × 2,350 |
| Regular estimate | KRW 124,370 | Truncate KRW 124,375 below KRW 10 |
| Special-work estimate at 7% | KRW 133,080 | 124,375 × 1.07, then truncate |
| Monthly reserve at 12 months | KRW 10,365 | 124,370 ÷ 12, rounded up to KRW 1 |
Why every money field starts at zero
Seoul’s price portal publishes different district figures, while Cheongju’s official guide uses another included volume and unit fee.
A national default would hide this difference and could create false confidence.
Load the Gwangjin case only to understand the arithmetic, then replace it with the latest tariff and quote for the facility’s locality.
Enforcement Decree Annex 8 fine-reference bands
Sewerage Act Article 80 paragraph 4 item 12 provides a fine ceiling of KRW 1 million for failure to perform the internal cleaning required by Article 39 paragraph 2.
Enforcement Decree Article 43 and Annex 8 provide the detailed amounts by facility size and first, second, or third-and-later violation.
A septic tank uses design population, while a sewage-treatment facility uses daily treatment capacity.
Korea private sewage facility missed-cleaning fine reference by size and count| Facility size | First | Second | Third or later |
|---|
| Sewage up to 2 m³/day or septic tank up to 10 people | KRW 100,000 | KRW 200,000 | KRW 300,000 |
| Sewage over 2 and below 5 m³/day or septic over 10 and below 20 people | KRW 200,000 | KRW 300,000 | KRW 400,000 |
| Sewage from 5 and below 10 m³/day or septic from 20 and below 30 people | KRW 300,000 | KRW 400,000 | KRW 500,000 |
| Sewage from 10 and below 20 m³/day or septic from 30 and below 50 people | KRW 400,000 | KRW 500,000 | KRW 600,000 |
| Sewage from 20 and below 50 m³/day or septic from 50 and below 100 people | KRW 500,000 | KRW 600,000 | KRW 800,000 |
| Sewage from 50 and below 300 m³/day or septic from 100 and below 500 people | KRW 600,000 | KRW 700,000 | KRW 900,000 |
| Sewage from 300 m³/day or septic from 500 people | KRW 700,000 | KRW 800,000 | KRW 1,000,000 |
The displayed amount is not a fine decision
The authority determines whether the duty applied, whether cleaning was missed, the legally counted violation number, and any adjustment or final assessment.
The calculator’s delayed-exposure figure simply adds the special-work estimate and the selected reference amount.
It excludes any administrative-execution cost that may arise if cleaning remains undone after a fine disposition under Sewerage Act Article 39.
Practical scenarios and records to keep
Owner-managed detached home
Use the certificate date and create a 30-day reminder for the annual plan after confirming no different local instruction applies.
Use the design population on the facility record, not the current number of occupants, for the fine-reference band.
Commercial or lodging operation
Confirm the special-area and business tests instead of assuming a six-month rule from the trading name.
Compare a daytime booking with a night surcharge and the operational interruption before choosing the appointment.
Rural property acquisition
Request the completion record, facility type and size, last certificate, tariff, and any notice before taking management responsibility.
Keep recurring cleaning cost separate from the one-time installation budget.
Closed or entirely unused building
Ask whether an extension is available and what documents must be submitted.
Change the planning cycle only after receiving the revised date or approval from the authority.
Before booking
- Facility type, design population, or daily capacity
- Last cleaning certificate and locally confirmed cycle
- Base included volume, excess unit, unit fee, and truncation
- Vehicle access, hose distance, underground or night premium
- Provider registration, written quote, and available date
After cleaning
- Cleaning date, volume, provider, and vehicle details
- Itemised base, excess, surcharge, and additional fee
- Certificate, receipt, payment evidence, and condition note
- Next planned date and a reminder 30 days before it
- Record location and contact details for a future manager
Do not substitute cleaning volume, rated facility size, and current occupant count for one another.
Quoted cleaning volume drives cost, design population or daily capacity selects a fine-reference band, and locality plus facility use affects the cycle question.
Frequently asked questions
Does every septic tank use exactly 12 months?
The general rule is at least once a year, but a limited six-month rule and an authority-approved extension can change the relevant date.
Confirm the facility’s locality, use, notice, and records.
Is every pension, restaurant, or lodging business on six months?
No.
The specified area and detailed business or facility conditions must apply together, and the Rule contains exclusions.
Ask the competent authority using the exact address and registered business category.
May I enter today when the last cleaning date is unknown?
An invented date can postpone the calculated reminder and hide risk.
Leave it blank and retrieve the certificate, previous manager’s record, provider record, or local-authority record first.
Can I use the Gwangjin amount in another locality?
Use it only to understand and verify the worked arithmetic.
Replace every fee input with the latest official tariff and provider quote for the actual locality.
Does a displayed fine reference mean a violation occurred?
No.
The calculator always shows the table amount for the selected size and count.
The authority determines the duty, due date, violation, legally counted recurrence, procedure, adjustment, and final assessment.
Are facility capacity and cleaning volume interchangeable?
No.
Design population or daily rated capacity selects the fine band, while quoted or measured cleaning volume drives the fee formula.
Retrieve each value from its own facility record or quote.
Official sources and maintenance date
Sources were checked on August 16, 2026.
The Sewerage Act reference is law ID 001815, master serial 276803, Articles 39 and 80.
The Enforcement Decree reference is law ID 005369, master serial 286151, Article 43 and Annex 8, annex serial ID 18137689.
The Enforcement Rule reference is law ID 008578, master serial 287447, Article 33, effective June 22, 2026.
Recheck the current text, effective dates, fine table, and local tariffs before a future release or booking.
Put the next cleaning date on the calendar
Enter the certificate date and the cycle confirmed by the competent authority, then create a 30-day reminder and monthly reserve.
Replace the tariff whenever the locality or provider updates its terms, and recalculate from the new certificate after cleaning.