This calculator is based on South Korea (Seoul) 2026 residential water and city gas rates. Enter your usage to instantly see base fees, water supply charges, water usage surcharges, sewage fees, and the final total for water bills, plus base fees, usage charges, and VAT for gas bills.
| Meter Size | Base Fee (KRW/month) |
|---|---|
| 15mm | 1,080 |
| 20mm | 3,000 |
| 25mm | 5,200 |
| 32mm | 9,400 |
| 40mm | 16,000 |
| 50mm | 25,000 |
| Rate Item | Rate |
|---|---|
| Water Supply (Residential) | 580 KRW/m³ |
| Water Usage Surcharge | 170 KRW/m³ |
| Sewage Charge | 480 KRW/m³ |
| Rate Item | Rate |
|---|---|
| Base Fee | 1,250 KRW/month |
| Usage Rate | 22.3617 KRW/MJ |
| Heat Value Factor | 42.94 MJ/m³ |
| VAT | 10% |
The base fee varies by meter size. Check the meter cover or ask your building manager for the diameter (mm). Most residential units use a 15mm or 20mm meter.
Enter your monthly water usage in m³. Check the difference between this month's and last month's meter readings, or look it up through the Seoul Waterworks Authority app.
Click Calculate to see the base fee, water supply charge, water usage surcharge, and sewage charge separately, along with your total water bill.
Enter your monthly city gas usage in m³. Find it by subtracting last month's meter reading from this month's reading, or check the gas company's app or your bill.
Usage in m³ is converted to MJ using the heat value factor (42.94 MJ/m³), then multiplied by the unit rate (22.3617 KRW/MJ) to get the usage charge. The base fee is added, then VAT (10%) is applied to the subtotal.
Click Calculate to see the base fee, energy used (MJ), usage charge, subtotal, VAT, and total gas bill. Compare with your actual billing statement to verify accuracy.
Seoul water bills consist of water supply charges and sewage charges. The water supply portion includes a base fee (by meter size), a usage charge of 580 KRW/m³, and a water usage surcharge of 170 KRW/m³ for water resource protection. The sewage charge is 480 KRW/m³.
Seoul city gas bills comprise a fixed base fee (1,250 KRW/month) and a usage charge. Usage in m³ is converted to MJ using an average heat value of 42.94 MJ/m³, then multiplied by 22.3617 KRW/MJ. VAT of 10% is applied to the sum of base fee and usage charge to arrive at the final bill.
Reference last month's usage to estimate this month's water bill. This helps you quantify the impact of conservation measures or increased summer water use.
Calculate the difference in gas bills by varying your usage. For example, see exactly how much you save by reducing usage by 10m³ per month.
Input estimated water and gas usage for a new home to preview monthly utility costs. Using the previous resident's usage data gives you a more accurate forecast.
Larger meter sizes can deliver higher water volumes and require bigger supply infrastructure. Larger meters are used for large buildings and commercial facilities, with correspondingly higher base fees. Most homes use 15mm meters with the lowest base fee.
The water usage surcharge (물이용부담금) supports sustainable water resource use and quality protection. It funds river basin management, upstream resident support, waterside land acquisition, and total pollution load management. The rate is 170 KRW/m³.
The sewage charge assumes that the same volume of water used is discharged as sewage. It is calculated by multiplying the water usage (m³) by the sewage rate (480 KRW/m³). Even if actual discharge differs, billing is based on water usage.
Gas bills are based on energy (MJ), not volume (m³), because the calorific value of gas can vary by source and season. Seoul's average heat value conversion factor is 42.94 MJ/m³. Multiply your m³ usage by 43 to get the actual energy consumed in MJ.
Water bills in Seoul are typically issued monthly or bimonthly depending on the district. Gas bills are issued monthly, covering usage from the previous meter reading date to the current one.
VAT is 10% of the subtotal (base fee + usage charge), truncated to the nearest won. For example, base fee 1,250 KRW + usage charge 10,000 KRW = subtotal 11,250 KRW. VAT = 1,125 KRW (11,250 × 10%).
For water: use water-saving devices, check for leaks, batch laundry and dishes. For gas: maintain proper boiler temperature (18-20°C), improve insulation, and use pot lids when cooking. The Korea Energy Agency offers free energy-saving consultations.
Learn everything about Seoul's water and city gas rate structures, calculation methods, and savings strategies.
Seoul's residential water bills are split between water supply and sewage charges. The water supply portion includes a base fee by meter size, a usage charge of 580 KRW/m³, and a water usage surcharge of 170 KRW/m³. The sewage charge is 480 KRW/m³. For a 15mm meter with 20m³ usage, the total water bill is approximately 25,680 KRW. Seoul's Waterworks Authority is expanding smart metering to help residents monitor usage and detect leaks early.
Gas billing converts m³ usage to energy units (MJ) using a heat value factor of 42.94 MJ/m³. For 30m³ of usage, that's 1,290 MJ. At 22.3617 KRW/MJ, the usage charge is approximately 29,184 KRW. Adding the base fee of 1,250 KRW gives a subtotal of 30,434 KRW, and with 10% VAT of 3,043 KRW, the total bill is approximately 33,477 KRW. The MJ-based rate system ensures consumers are charged fairly regardless of gas calorific value fluctuations.
With climate change and rising energy prices, water and gas conservation is increasingly important. Local governments offer subsidies for water-saving devices, energy efficiency programs, and smart home integration services. Smart meter rollouts enable real-time monitoring and early detection of leaks and gas anomalies. Future changes may include hydrogen-blended gas supply and renewable energy-based heating systems, which could alter gas rate structures. Building conservation habits contributes both to lower bills and to carbon neutrality goals.