H 201.0 Capacity of Septic Tanks
TABLE H 201.1(1)
CAPACITY OF SEPTIC TANKS1, 2, 3, 4
| SINGLE-FAMILY DWELLINGS - NUMBER OF BEDROOMS | MULTIPLE DWELLING UNITS OR APARTMENTS - ONE BEDROOM EACH | OTHER USES: MAXIMUM FIXTURE UNITS SERVED PER TABLE 702.1 | MINIMUM SEPTIC TANK CAPACITY (gallons) |
|---|---|---|---|
| 1 or 2 | — | 15 | 750 |
| 3 | — | 20 | 1000 |
| 4 | 2 units | 25 | 1200 |
| 5 or 6 | 3 | 33 | 1500 |
| — | 4 | 45 | 2000 |
| — | 5 | 55 | 2250 |
| — | 6 | 60 | 2500 |
| — | 7 | 70 | 2750 |
| — | 8 | 80 | 3000 |
| — | 9 | 90 | 3250 |
| — | 10 | 100 | 3500 |
For SI units: 1 gallon = 3.785 L
Notes:
1 Extra bedroom, 150 gallons (568 L) each.
2 Extra dwelling units over 10: 250 gallons (946 L) each.
3 Extra fixture units over 100: 25 gallons (94.6 L) per fixture unit.
4 Septic tank sizes in this table include sludge storage capacity and the connection of domestic food waste disposers without further volume increase.
TABLE H 201.1(2)
DESIGN CRITERIA OF FIVE TYPICAL SOILS
| TYPE OF SOIL | REQUIRED SQUARE FEET OF LEACHING AREA PER 100 GALLONS | MAXIMUM ABSORPTION CAPACITY IN GALLONS PER SQUARE FEET OF LEACHING AREA FOR A 24 HOUR PERIOD |
|---|---|---|
| Coarse sand or gravel | 20 | 5.0 |
| Fine sand | 25 | 4.0 |
| Sandy loam or sandy clay | 40 | 2.5 |
| Clay with considerable sand or gravel | 90 | 1.1 |
| Clay with small amount of sand or gravel | 120 | 0.8 |
For SI units: 1 square foot = 0.0929 m2, 1 gallon = 3.785 L, 1 gallon per square foot = 40.7 L/m2
TABLE H 201.1(3)
LEACHING AREA SIZE BASED ON SEPTIC TANK CAPACITY
| REQUIRED SQUARE FEET OF LEACHING AREA PER 100 GALLONS SEPTIC TANK CAPACITY (square feet per 100 gallons) | MAXIMUM SEPTIC TANK SIZE ALLOWABLE (gallons) |
|---|---|
| 20—25 | 7500 |
| 40 | 5000 |
| 90 | 3500 |
| 120 | 3000 |
For SI units: 1 square foot per 100 gallons = 0.000245 m2/L, 1 gallon = 3.785 L
TABLE H 201.1(4)
ESTIMATED WASTE/SEWAGE FLOW RATES1, 2, 3
| TYPE OF OCCUPANCY | GALLONS PER DAY |
|---|---|
| Airports (per employee) | 15 |
| Airports (per passenger) | 5 |
| Auto washers — check with equipment manufacturer | - |
| Bowling alleys — with snack bar only (per lane) | 75 |
| Campground — with central comfort station (per person) | 35 |
| Campground — with flush toilets — no showers (per person) | 25 |
| Camps (day) — no meals served (per person) | 15 |
| Camps (summer and seasonal camps) — (per person) | 50 |
| Churches — sanctuary (per seat) | 5 |
| Churches — with kitchen waste (per seat) | 7 |
| Dance halls — (per person) | 5 |
| Factories — no showers (per employee) | 25 |
| Factories — with showers (per employee) | 35 |
| Factories — with cafeteria (per employee) | 5 |
| Hospitals — (per bed) | 250 |
| Hospitals — kitchen waste only (per bed) | 25 |
| Hospitals — laundry waste only (per bed) | 40 |
| Hotels — no kitchen waste (per bed) | 60 |
| Institutions — resident (per person) | 75 |
| Nursing home — (per person) | 125 |
| Rest home — (per person) | 125 |
| Laundries — self-service with minimum 10 hours per day (per wash cycle) | 50 |
| Laundries — commercial check with manufacturer's specification | - |
| Motel (per bed space) | 50 |
| Motel — with kitchen (per bed space) | 60 |
| Offices — (per employee) | 20 |
| Parks — mobile homes (per space) | 250 |
| Parks (picnic) — with toilets only (per parking space) | 20 |
| Parks (recreational vehicles) — without water hook-up (per space) | 75 |
| Parks (recreational vehicles) — with water and sewer hook-up (per space) | 100 |
| Restaurants — cafeteria (per employee) | 20 |
| Restaurants — with toilet waste (per customer) | 7 |
| Restaurants — with kitchen waste (per meal) | 6 |
| Restaurants — with kitchen waste disposable service (per meal) | 2 |
| Restaurants — with garbage disposal (per meal) | 1 |
| Restaurants — with cocktail lounge (per customer) | 2 |
| Schools staff and office (per person) | 20 |
| Schools — elementary (per student) | 15 |
| Schools — intermediate and high (per student) | 20 |
| Schools — with gym and showers (per student) | 5 |
| Schools — with cafeteria (per student) | 3 |
| Schools (boarding) — total waste (per person) | 100 |
| Service station — with toilets for 1st bay | 1000 |
| Service station — with toilets for each additional bay | 500 |
| Stores — (per employee) | 20 |
| Stores — with public restrooms (per 10 square feet of floor space) | 1 |
| Swimming pools — public (per person) | 10 |
| Theaters — auditoriums (per seat) | 5 |
| Theaters — with drive-in (per space) | 10 |
For SI units: 1 square foot = 0.0929 m2, 1 gallon per day = 3.785 L/day
Notes:
1 Sewage disposal systems sized using the estimated waste/sewage flow rates shall be calculated as follows:
(a) Waste/sewage flow, up to 1500 gallons per day (5678 L/day)
Flow × 1.5 = septic tank size
(b) Waste/sewage flow, over 1500 gallons per day (5678 L/day)
Flow × 0.75 + 1125 = septic tank size
(c) Secondary system shall be sized for total flow per 24 hours.
2 See Section H 201.1.
3 Because of the many variables encountered, it is not possible to set absolute values for waste/sewage flow rates for all situations. The designer should evaluate each situation and, where figures in this table need modification; they should be made with the concurrence of the Authority Having Jurisdiction.