Barrel Composting Toilet System:
Construction Materials List

(Updated 10/14/2014)

MATERIALS AND COST ESTIMATE IS FOR A 3 BARREL SYSTEM, SIZED FOR 2 ADULTS IN FULL-TIME USE

BARRELS:

--3          55 GALLON POLYETHYLENE BARRELS, NEW, BLACK                                                                 $148      
              (NOTE:  USED BARRELS ARE TYPICALLY $15 AND UP)

BARREL TOP ASSEMBLY (FOR ACTIVE BARREL):

BARREL TOP:

--1          ¾” X 2’ x 2’  HARDWOOD PLYWOOD (SEE BOTTOM OF CONSTRUCTION
              MANUAL PAGE FOR INFORMATION ON ALUMINUM AND CONCRETE TOPS)                            $ 11       
--1          ½ PINT VARNISH OR EXTERIOR PAINT                                                                                          $   6
--1

TOILET SEAT ASSEMBLY:

--1          WOOD TOILET SEAT, ROUND                                                                                                          $   7       
--1          1/4” X 1/2” x 17’ CLOSED-CELL ADHESIVE WEATHERSTRIP                                                        $   6       
--1          3/8” x 1/2” X 10’ CLOSED-CELL ADHESIVE WEATHERSTRIPPING                                               $   5       
--1          ¼” x 1” x 10’ CLOSED CELL ADHESIVE WEATHERSTRIPPING                                                     $   5       
 

VENT ASSEMBLY:

--1          3” ABS SANITARY TEE, HUB X HUB X HUB                                                                                     $   6       
--2          2” ABS VENT ELBOWS, SLIP X SLIP                                                                                                $   6       
--2          PIECES OF 2" ABS PIPE, EACH 2-1/4” LONG (@ $2 PER FOOT)                                                   $   1       
--1          PIECE OF 3” ABS PIPE, 3" LONG (@ $4 PER FOOT)                                                                      $   2      
--1          SMALL CAN, ABS PIPE CEMENT                                                                                                     $   4
--4          2-3/4” HOSE CLAMPS, STAINLESS STEEL (@ $1 APIECE)                                                            $   4       
--2          4” HOSE CLAMPS, STAINLESS STEEL (@ $1.50 APIECE)                                                             $   3       
--1          12” X 12” ALUMINUM INSECT SCREEN                                                                                           $   1
--1          12" x 12" NO-SEE-UM NETTING                                                                                                        $   2

LOCATOR BOLT ASSEMBLY:

--4          ¼” X 2-1/2” CARRIAGE BOLTS, STAINLESS STEEL                                                                        $   4
--4          ¼” FLAT WASHERS , STAINLESS STEEL                                                                                         $   1
--4          ¼” NUTS STAINLESS STEEL                                                                                                             $   1
 

HOLD-DOWN SPRING ASSEMBLY:

--4          1-1/2" LONG SCREW EYES                                                                                                               $  1
--4          EXTENSION SPRINGS
                SERVALITE #70, 7/16” OD X 5” LONG, 0.41 WIRE GAUGE, OR:
                HILLMAN #66, 6-3/4” OVERALL LENGTH X 15/32” X 0.47 WIRE GAUGE                                     $  10
--12        #10 X ¾” PAN HEAD MACHINE SCREWS, STAINLESS STEEL                                                      $  2
--24        #10 FLAT WASHERS, STAINLESS STEEL                                                                                        $  5
--24        #10 NUTS, STAINLESS STEEL                                                                                                          $  4

SCREEN ASSEMBLY (FOR 2 AGING BARRELS)

--2          3’ X 3’ FIBERGLASS INSECT SCREEN                                                                                             $  6  
--2          1/8” X 7’ BRAIDED NYLON CORD                                                                                                     $  2
--2          EXTENSION SPRING, SERVALITE #112, ¼” OD X 3-1/2” LONG, O.41 WIRE
                GAUGE                                                                                                                                              $  4
 

RAIN COVER (FOR 2 AGING BARRELS)

--2          2’ 3” X 2’ 3” CORRUGATED STEEL ROOFING PANEL                                                                     $  10
--4          2” X 8” X 16” CEMENT PATIO BLOCKS                                                                                             $   5

INSECT TRAP:

--1          1 QUART CANNING JAR, WIDE MOUTH                                                                                          $  1
--1          CANNING JAR RING, WIDE MOUTH                                                                                                 $  1
--1          2 QUART SODA BOTTLE, CLEAR PLASTIC, TYPE PETE                                                               $  0
 

COMPOST CRANK:

--1          COMPOST CRANK                                                                                                                            $43

COMPOST CRANK RECEPTACLE:

--1          4” X 30” ABS PIPE                                                                                                                              $10

TOTAL FOR 3 BARREL SYSTEM USING ALL NEW MATERIALS =                           $327
                (FOR A LARGER SYSTEM, ADD $68 FOR EACH ADDITIONAL
                BARREL.)     

--Barrels:   55-gallon high-density polyethylene barrels as described on these web pages are the commonly available type with top intact and two bung holes in the top.  Metal barrels will corrode and should not be used.  Polyethylene barrels with removable tops can be used, but will require a toilet top assembly different than that described here.  For UV protection, barrels should be black if used in an outdoor installation.  Or, barrels can be painted black with 3 coats of black oil-base enamel.   Used barrels are often available at dairies and bakeries for about $15 apiece, reducing the above cost estimate by approximately $35 per barrel.  However, in the event this design is eventually permitted by regulatory authorities, used barrels might not be allowed under a permit. 

--Plywood top: Hardwood plywood is available in 2' square pieces at major building supply centers.  Plywood with hardwood exterior veneers is recommended as it is more resistant to surface checking than softwood veneers. NOTE: See bottom of Construction and Installation Manual for alternative top material suggestions.

--Toilet seat: Plastic seats are difficult to seal with weatherstrip to prevent insects from entering the active barrel.  Wood seats are much easier to effectively weatherstrip.

--Weatherstrip:  Should be closed-cell foam to prevent absorption of urine and consequent odors.

--Rain cover:  Two 2" x 8" x 16" patio blocks per rain cover are minimum.  3-4 should be used in windy locations.   

--Compost Crank:  Can be found online at this link.  We have tried a variety of other compost aeration tools, but none is as effective as the Compost Crank.  The Compost Crank is an essential component of the Barrel Composting Toilet system and we do not recommend substitutes.  (We do not sell this tool or have any financial connection with Lotech Products, the manufacturer of this product.)

Barrel Composting Toilet Page