2026-10-23T18:23:57

Septic Tank Size per SNI 2398:2017: Dimensions by Users, Distances and Pipes

Septic tank size per SNI 2398:2017 depends on the number of users and the desludging interval. For a mixed system (toilet plus greywater) with 3-year desludging, Table 2 of the standard gives 5 users = 1.6 x 0.8 x 1.6 m (2.1 m3) and 10 users = 2.1 x 1.0 x 1.8 m (3.9 m3). This article summarises the size table, the septic tank distance from a well, pipe diameters and infiltration from the standard text we read on 23 October 2026, plus a homeX calculation.

Septic tank size per SNI 2398:2017 by users: table, distances and pipes

Item	Value in the standard	Detail	homeX note	Source
Mixed system, 5 users	1.6 x 0.8 x 1.6 m; total 2.1 m3	Table 2, 3-year desludging	homeX check: 1.6 x 0.8 x 1.6 = 2.05 m3, matching the table	SNI 2398:2017 (BSN, salinan PDF)
Mixed system, 10 users	2.1 x 1.0 x 1.8 m; total 3.9 m3	Table 2	homeX check: 3.78 m3 from the dimensions; the table rounds to 3.9	SNI 2398:2017 (BSN, salinan PDF)
Mixed system, 15 / 20 / 25 users	2.5 x 1.3 x 1.8 (5.8 m3); 2.8 x 1.4 x 2.0 (7.8 m3); 3.2 x 1.5 x 2.0 (9.6 m3)	Table 2; 50 users = 4.4 x 2.2 x 2.0 m (19.4 m3)	Suits boarding houses, small offices or shophouses	SNI 2398:2017 (BSN, salinan PDF)
Separate system (toilet only)	10 users 1.6 x 0.8 x 1.3 m (1.66 m3); 25 users 2.4 x 1.2 x 1.6 m (4.6 m3)	Table 2; the table has no 5-user entry for the separate system	Kitchen and bathing water is treated separately	SNI 2398:2017 (BSN, salinan PDF)
Shape and minimum dimensions	Rectangular, length:width 2:1 to 3:1; min width 0.75 m; min length 1.50 m; min height 1.5 m including 0.3 m freeboard	Clause 4.2.1.2 a)	Inspection hole at least 0.40 x 0.40 m, rim 10 cm above ground	SNI 2398:2017 (BSN, salinan PDF)
Distance of infiltration from buildings, wells and rain wells	Building 1.5 m; drinking-water well 10 m; rain infiltration well 5 m (well/field); up flow filter and sanitary garden 1.5 m to all three	Table 1, unless special treatment applies	Consistent with SNI 8456:2017 (5 m from a rain infiltration well)	SNI 2398:2017 (BSN, salinan PDF)
Waste pipe, slope and clean-out	PVC min 110 mm (4 in); min slope 2%; clean-out at bends over 45 degrees and 22.5 degree changes; a 90 degree bend = two 45 degree bends or an inspection chamber	Clause 4.2.1.2 b)	See PVC class D and AW pipes in the related homeX article	SNI 2398:2017 (BSN, salinan PDF)
Inlet, outlet and vent pipe	Outlet 63–110 mm lower than the inlet; T-junction submerged 200–315 mm; vent pipe 63 mm, at least 250 mm above ground	Clause 4.2.1.2 c) and d)	Vent end faces down with a mesh screen	SNI 2398:2017 (BSN, salinan PDF)
Infiltration well (max 10 users)	Diameter 800 mm, depth 1.00 m, filled with 30–80 mm gravel or crushed stone	Clause 4.2.2.1	Only for small tanks and a low water table	SNI 2398:2017 (BSN, salinan PDF)
Infiltration field (two lines)	I = 600 L/m2/day (0.10 m/h drop): 5 users 1.0 m; 10 users 2.0 m; 25 users 5.0 m; I = 120: 5 users 5.0 m, 25 users 25 m	Table 4 and Table 7; trench width min 500 mm, effective depth min 450 mm	Infiltration pipe over 15 m needs 2 lines, axis spacing at least 1.5 m	SNI 2398:2017 (BSN, salinan PDF)

Source: the text of SNI 2398:2017 (PDF copy on the Yogyakarta city government site) read directly on 23 October 2026, covering Tables 1, 2, 4 and 7 and clause 4.2. The standard applies to up to 50 users. Data gaps: the tables give no prices, excavation costs or brands; local soil absorption and water-table checks are still needed; local regulations may differ; factory-made (bio) septic tanks have their own specifications.

Septic tank size for a 5-person house: homeX calculation

homeX analysis, not standard data. A 5-person family house uses a mixed system: internal size 1.6 x 0.8 x 1.6 m. Add wall thickness of about 12–15 cm (brick) and the cover slab, so the excavation is roughly 2.0 x 1.2 x 2.0 m. With absorption of 600 L/m2/day, a two-line field needs only 1.0 m per Table 4, but soil with low absorption (120) needs 5.0 m. Your own soil value must be tested, not assumed.

Concrete, brick or factory-made (bio) septic tank?

Table 3 of the standard allows plastered river stone, red brick or concrete block, unreinforced concrete, FRP and reinforced concrete for the tank body; all must be watertight. Factory bio septic tanks have their own sizes and claims; compare prices in the homeX article on bio septic tanks and do not equate them with the table figures above.

Buyer tips

Count users (including guests and boarders) before choosing the size.
Keep at least 10 m from a drinking-water well and 1.5 m from the building.
Lay 110 mm pipe at a minimum 2% slope with clean-outs at every bend.
Ask for a soil percolation test and measure the water table before digging the infiltration.

Request a septic tank size per SNI 2398 quote for your project

homeX can compare several brands at once and prepare a written quote for projects, renovations or shop stock. Send your needs (brand, size, quantity, location) via WhatsApp +62 821 1818 998, or visit the homeX showroom: Priskilla Tower, 6th floor, Jl. Atang Sanjaya No.21, Benda, Kota Tangerang, Banten 15125. Visit the homeX Showroom.

Disclaimer: prices change without notice and differ by store, city, pack size, grade and promotion. Data as of 23 October 2026; always confirm with the seller before buying.

FAQ

What size septic tank for 5 users per SNI? Mixed system with 3-year desludging: 1.6 x 0.8 x 1.6 m (total volume 2.1 m3) per Table 2 of SNI 2398:2017.

How far should a septic tank be from a well? Table 1 of the standard: effluent infiltration at least 10 m from a drinking-water well, 5 m from a rain infiltration well and 1.5 m from buildings; local soil conditions may demand more.

How often should a septic tank be desludged? The size table in SNI 2398:2017 is based on a 3-year desludging period; the design criteria cite a 2–5 year range.