Small Modular Code for Water, Drain, Waste, Vent and Tankless Water Heater

If you are designing your own plans for a small house, it can be hard to figure out what is going to conform to the building code.

Plans for our 763 square foot cabin have been reviewed and for compliance with NC Codes. The building code near you may not be identical, but it will be close. This information may be helpful.

The first page, General Notes specifies;

This unit must be connected to a public power, water supply and sewer system if these are available.

Drain/Waste/Vent Detail
Plumbing Isometrics and Details
Westwood Cabins Creekside Manor 3016
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Drain/Waste/Vent Details

DWV Riser Notes

Change in direction in schedule 40 DWV-PVC and abs drainage piping shall be made by the appropriate use of 45° (0.785 RAD) wyes, quarter bends, or long sweep quarter bends, one-sixth, one-eighth, one-sixteenth bends, or by a combination of these or equivalent fittings. Single and double sanitary tees and quarter bends may be used in drainage lines only where the direction flow is from the horizontal to the vertical.

Short sweeps not less than 3 inches diameter may be used in soil and waste lines where the change in direction of flow is from the horizontal to the vertical and may be for making necessary offsets between the ceiling and the next floor above.

Slope of Horizontal Drainage Piping
2-1/2″ or less: 1/4″ slope per foot
3 to 6″: 1/8″ slope per foot

Details, Construction and Final Photos of Drain/Waste/Vent Plan >

Cold & Hot Water Supply Detail

Shut Off Valves

All plumbing fixtures shall have separate shut-off valves (tubs and showers located in floor cavity, sinks located in cab. base)

Hose Bib

Hose bibs to have backflow preventers (hose bibs are optional)

Pipe Support

PEX: horizontal= 2′-8″, vertical= 10′
Copper: horizontal= 12′, vertical= 10′
CPVC: horizontal= 4′, vertical= 10′
PVC: horizontal= 4′, vertical= 10′

Max design pressure = 80 psi
Min. Design pressure = 40 psi
Max developed length = 80′

Details, Construction and Final Photos of Water Plan >

Tankless Water Heater Detail

Tankless Water Heater Notes

Tankless water heater to be installed in accordance with manufacturers recommendations.
Per 2018 NC energy code, section r403.5.3
– Hot water lines 3/4″ and larger within conditioned space shall be insulated to an R-3 minimum.
– All hot water lines outside conditioned space shall be insulated to an R-3 minimum.

Water Temperature Control in Piping from Tankless Heaters

The temperature of water from tankless water heaters shall be not greater than 140°f (60°c) where intended for domestic uses. This provision shall not supersede the requirement for protective shower valves in accordance with section 424.3

The page with Electrical Diagrams and Schedules shows two breakers in the service panel run to the water heater.

Below, the Plumbing Specs and Notes specifies;

Electric Tankless Water Heater: rectangular type; 24kw on demand water heater, 240 v, 150 lb. working pressure, thermostat and safety controls, relief valve safety and temperature controls, 6 year warranty, u.l. listed and approved, Tempra 24 plus or approved equal.

Construction and Final Photos of On-Demand Water Heater Plan Details>

Plumbing Isometrics and Details General Notes

All plumbing fixtures shall have separate shut-off valves.
DWV system shall either be abs or PVC-DWV.
Water supply lines shall be CPVC (sch 40 or scrii) or PEX. Water supply lines may be stubbed through the floor (only) with the on-site installation of all lines below the floor to be in accordance with the specifications on this drawing.
Water closets average water usage shall not exceed 1.6 gal/flush.
Building drain and cleanouts are designed and site installed by others, subject to local jurisdiction approval. Under floor trap arms not installed in the factory cue to possible in-trANSIt damage are to be site installed in accordance with the specifications on this drawing.
An accessible shut off valve shall be provided ahead of the first outlet or branch connection to the service or distribution pipe. This shut off valve may be site installed.
Sinks and lavs shall not use more than 2.2 gal/min @ 60 psi.
Shower heads shall not use more than 2.5 gal/min @ 80 psi
All showers to have temperature of water controlled by a balanced pressure, thermostatic or combination balanced pressure/thermostatic valve to limit the water temp to 120°f (valve to comply w/ asse 1016 or csa can/csa-b125).
Air admittance valves (AV) shall conform to ASSE 1051. the AV valves shall be located a minimum of 4 inches above the horizontal drain or fixture drain being vented and must be installed in well ventilated spaces or be provided with ventilated access doors.
Water hammer arrestors to be installed where quick closing valves are utilized (i.e. dishwashers, clothes washers, ice makers, or other quick closing devices with solenoid valves). Arrestors must comply with ASSE/ANSI 1010 and must be installed in accordance with the manufacturer’s instructions.
An approved thermal expansion device shall be site installed in the water supply system in accordance with the manufacturer’s installation instructions. (This devise is required when backflow preventors, pressure reducing valves, check valves, or storage water heaters are installed in the water supply system which may prevent pressure relief.
Vents must be 6″ above the level rim of the highest fixture served before it can go horizontal.

Plumbing Specs and Notes:

Installation and workmanship to be first class as generally accepted in trade. Entire installation to be per 2018 North Carolina residential code and per all local codes and ordinances. Owner, architect and engineer will interpret the meaning of all drawings and shall have the power to reject any work not, in their judgment, in full accordance therewith. Work shall include all equipment, fees, tools and plant labor, etc., required for installation of complete plumbing systems. All materials for the job to be new.
Waste & vent piping: plastic soil and waste pipe shall be PVC, schedule 40 DWV piping and fittings, nsf approved, conforming to ASTM-c1785 and ASTM c-2665, cs-272-65 and cs-270-65. Pipe shall be as manufactured by charlotte plastic company or approved equal. All change of direction fittings to be long sweep type.
Plastic water pipe and fittings: CPVC plastic pipe shall be used for all cold and hot water supply piping, except that exposed supplies to plumbing fixtures shall be C.P. brass. Fittings to be solvent type.
Sanitary system accessories:
A. cleanouts: shall be schedule 40 PVC with C.P. cover where exposed on interior of building.
B. roof flashings: 6 lb. Per sq. ft. lead sheets extending 24″ around pipe and turned into top of pipe, as approved by the roofing contractor.
Water system accessories:
A. shock absorbers: elastomer bellows type immersed in glycerine displacement fluid, stainless steel shell or reinforced bellows type, Josam series 15500 or approved equivalent as manufactured by Wade mfg. co., or Zurn co., size indicated on the drawings.
Valves for water systems:
A. gate, and check valves, 2″ and smaller, shall be all brass or bronze, screwed type with adaptor or solder type. Valves shall be three section ball valves with Teflon seals, chrome plated or stainless steel ball, watts no. 6800 or equal as manufactured by Hammonds or Apollo.
B. All valves shall be designed for 125 p.s.i. steam working pressure.
Pipe insulation (except pipe in urethane insulation) hot water piping:
A. Insulation for hot water pipe: shall be 3/4″ foamcell armaflex insulation with self-adhering joints and seams and taped with manufacturer supplied armaflex tape.
B. Insulation for cold water pipe: none required.
C. All new hot water pipe, except where concealed in wall and except C.P. supplies to fixtures, shall be covered. Insulation to be installed by licensed insulation contractor with minimum 5 years experience.
Pipe hangers:
A. Hangers to be of size to fit outside covering on insulated pipes.
B. Hangers for steel pipe shall be split-ring type with adjustable swivel hanger Grinnell fig. no. 104 or clevis type Grinnell fig. no. 260. c. hangers for PVC pipe shall be hanger and trough type. All hangers shall be furnished complete with hanger rocs, and structural attachments. Sheet metal saddles 12″ long x 1/2 insulated pipe diameter shall be used at each hanger point on all covered pipe.
C. Approved equivalent hangers as manufactured by f & s, b-line, Modern, or Grabler, will be acceptable.
Plumbing fixtures:
A. Plumbing fixtures shall be furnished complete with all equipment, fittings, trimmings, traps, stops on water supplies.
B. The numbers referred to, for the fixtures below are those of the Kohler company for plumbing fixtures and Delta for brass supply fittings. Plumbing fixtures manufactured by the American Standard company, Crane, or Eljer, will be acceptable.
C. All fixtures shall be of the best grade, trademarks and labels designating the quality for class of the fixtures shall be affixed to all fixtures and shall not be removed until after the work has been accepted. All vitreous china shall be in accordance with the requirements of the US department of commerce applying to staple vitreous china plumbing fixtures.
D. Exposed metal pipes to fixtures shall be brass, chromium plated and all piping from fixtures passing into wall shall be provided with chromium plated brass escutcheons with set screw.

Water Closet: vitreous china, white, Kohler Wellworth no. k-3575-0 floor mounted, elongated, 1.28 GPF, quiet-type, tank type water closet with church no. 9500 or Olsonite no. 95 white open front seat, with C.P. supplies with stop.

Lavatory : vitreous china, white, Kohler no. k2699-4-0, “Bryant” oval counter mounted lavatory with mounting accessories, with 17 gauge C.P. “P” trap, with c.o. And wall escutcheon, with C.P. supplies and stops and with Delta no. 501-wf single lever supply faucet 0.5 gpm aerator and pop up drain.

Kitchen Sink: shall be ledge type, double bowl, 20 gauge, type 302 stainless steel sink, self-rimming Elkay no. cr-3321, overall size 33″ x 21 1/4″ x 7″ deep with single lever deck mounted swing spout faucet, Delta no. 400 lf-wg, with 2.0 gpm aerator with C.P. crumb cup strainer and tail piece, C.P. “P” trap and with integral mounting frame and sound deadening under side with holes to fit faucet above.

Shower Cabinet : 32″ x 34″ x 84″ high one piece molded acrylic shower without joints and seams and shall meet ANSI a117.1 and z124.2. unit to be predrilled and shall be provided with towel bar, brass drain with stainless steel strainer, stainless steel curtain roc, factory installed. Provide with Delta no. 1424-lhp pressure balance mixing valve, comply with ANSI / ASME a112.18.1m and ANSI / asse 1016, and 2.1 gpm @ 60 p.s.i. shower head. Shower to be Aquarius no. A3234 or equal.

Electric Tankless Water Heater: rectangular type; 24kw on demand water heater, 240 v, 150 lb. working pressure, thermostat and safety controls, relief valve safety and temperature controls, 6 year warranty, u.l. listed and approved, Tempra 24 plus or approved equal.

Washer Box: Sioux Chief no. 696-2313cf. With ball valve shutoff, shock absorbers and 2″ waste outlet.

Cleaning and Tests:

The entire new system of domestic water piping shall be entirely blown out and flushed so as to remove all dirt and grease.

Upon completion of the cleaning, and after testing is complete, the shutoff valve to the domestic water main shall be closed, all fixture outlets opened slightly and a chlorine solution introduced at a manifold connection installed by the plumbing contractor on the system side of the system shutoff valve at the water main. The chlorine solution shall contain not less than 50 parts per million of chlorine and shall be liquid or sodium hypochlorite. Solution shall be introduced into the system in such a manner as to insure the dispersion of the solution throughout the entire system and the orthololicin test at each outlet shall show residual chlorine. The solution shall remain in the system not less than 24 hours after which the entire system shall be flushed so as to drain off solution. After flushing all aerators shall be removed, cleaned and replaced.
All new water piping shall be tested to not less than 150 lbs., hydrostatic and the piping shall remain tight for a period of two hours.

All traps, wastes, and supplies shall be shown to be free and unobstructed. All new plates, polished, bronze and painted work, shall be bright and clean. Just before final inspection the contractor shall thoroughly clean all equipment, piping and other exposed work. The contractor shall make all necessary adjustments for flush valves, fittings and automatic controls for quiet and proper operation.

The entire new drainage system shall be tested in its entirety, or may be tested in sections. Each section shall be filled with water to a point ten feet (10′) above the horizontal pipe in the section. The piping shall remain tight for a period of one hour. Where local regulations require smoke test, the contractor shall make this test in accordance with local regulations.

Tests as required shall also be performed for any authorities having jurisdiction.

Pipe Routing: piping shall be routed concealed in room walls and in drawl space.