NAC445A.9656. Septic tanks: Minimum capacity determined by projected daily sewage flow.

     1. The minimum capacity of a septic tank used in an on-site sewage disposal system must be based on the projected daily sewage flow and other considerations specified in subsections 2 to 5, inclusive. The following table may be used to determine the projected daily sewage flow, using the occupancy that most closely resembles the anticipated occupancy of the building:

TYPE OF OCCUPANCY	PROJECTED FLOW OF SEWAGE (GALLONS PER DAY)
Airports	15 per employee and 5 per customer
Automobile washes (sand/oil interceptor required)	5 per passenger vehicle
Bowling alleys	150 per lane
Camps:
Campground with central comfort station	35 per person
With flush toilets, no showers	25 per person
Day camps (no meals served)	15 per person
Summer and seasonal	50 per person
With cocktail lounge	Add 2 per meal served
With garbage disposal (not recommended)	Add 1 per meal served
With kitchen waste	Add 6 per meal served
With kitchen waste, disposable service	Add 2 per meal served
Schools:
Teaching staff and other employees	20 per person
Kindergarten or elementary school	15 per pupil
Junior high school, middle school or high school	20 per pupil
With gym and showers	Add 5 per pupil
With cafeteria	Add 3 per pupil
Boarding school (including all waste)	100 per person
Service stations:
With toilets	1,000 for first bay
Each additional bay	Add 500
Stores or shopping centers:
Staff	20 per employee
With public restroom	1 per 10 square feet of floor space
Swimming pools (public)	10 per person
Theaters and auditoriums:
Indoor	5 per seat
Drive-in	10 per space

     2. If the projected daily sewage flow for the intended occupancy is 3,000 gallons or less per day, the minimum capacity of the septic tank must be equal to the projected daily sewage flow multiplied by 1.5.

     3. If the projected daily sewage flow for the intended occupancy is more than 3,000 gallons per day, the minimum capacity of the septic tank must be equal to the projected daily sewage flow, with an additional sludge storage volume of 1,500 gallons.

     4. If the projected daily sewage flow includes waste from recreational vehicles, the minimum capacity of the septic tank must be equal to the projected daily sewage flow multiplied by 2, to provide sufficient treatment capacity for the generally higher strength of recreational vehicle sewage and the common sanitary solution additives that inhibit microbial activity. In addition, increased pumping frequency must be specified in the operations and maintenance manual prepared pursuant to NAC 445A.970.

     5. Septic tanks serving establishments with high sewage volume, including, without limitation, restaurants, convenience stores and service stations located near interstate highway exits, require special sizing considerations. The minimum capacity of such a septic tank must be equal to the projected daily sewage flow multiplied by 3.

     (Added to NAC by Environmental Comm’n by R194-07, eff. 8-26-2008)