66" × 36" Alcove Bathtubs
Standard alcove bathtub dimensions — the most common size for home bathrooms in the US. Fits a 3-wall alcove installation. This page tracks research on available models, specs, and buying considerations.
image: Hydro Systems Sydney product image via QualityBath
Hydro Systems Sydney — SYD6636ATO-WHI-LH
- Configuration: 66″ × 36″ alcove soaking tub, white, left-hand drain.
- Install package: acrylic tub only with skirt and tile flange / 3-wall alcove setup.
- Published reference specs: 66″ L × 36″ W × 20″ H, rectangular acrylic, slip-resistant bottom, skirt, tile flange, overflow, approximately 70 gallons to overflow.
- Ordering note: confirm the exact suffix
-WHI-LH, left-hand drain orientation, flange/skirt configuration, lead time, and compatible waste/overflow before release.
Why 66" × 36"?
The 66" length fits standard 5-foot alcove openings while the 36" width provides more interior space than the narrower 32" alcove models. It's a practical middle ground — spacious enough for soaking, fits standard framing, and widely stocked by major retailers.
Key Specs to Compare
- Length × Width (outer): 66" × 36" — confirm rough-in framing
- Height: typically 19"–21"
- Water depth: 14"–16" — deeper is better for a true soak
- Basin length × width: where your body actually sits — often 42"–48" × 24"
- Water capacity: 45–55 gallons typical
- Drain side: left-hand vs. right-hand — must match your plumbing
- Material: acrylic, fiberglass/acrylic composite, or enameled steel
- Integrated flange: helps waterproof the alcove seam
Known Models
Hydro Systems Sydney — SYD6636ATO-WHI-LH
image: Hydro Systems Sydney product image via QualityBath
| Spec | Value |
|---|---|
| Dimensions | 66″ L × 36″ W × 20″ H |
| Drain | Left-hand |
| Material | Acrylic |
| Features | Skirt, tile flange, slip-resistant bottom, overflow |
| Capacity | Approximately 70 gallons to overflow |
| Status | Selected |
Kohler Mariposa — K-1229-L
image: shopkohlernj.com (authorized Kohler dealer)
| Spec | Value |
|---|---|
| Dimensions | 66" L × 35-7/8" W × 21-1/4" H |
| Water depth | 14" |
| Basin | 48" L × 24" W |
| Drain | Left-hand |
| Material | Acrylic |
| Features | Integral flange, embossed bathing well |
| Approx. price | $$$ (premium) |
Note: K-1229-L is the flanged variant without an apron. The residential apron version is K-1229-LA-0.
PROFLO Hillsboro / Plus Series — PFS6636LSKWH
image: American Bath Group via royalbathplace.com
| Spec | Value |
|---|---|
| Dimensions | 66" L × 36" W × 19-3/4" H |
| Basin | 42" L × 24" W |
| Drain | Left-hand |
| Material | Acrylic |
| Features | Skirted front, integrated tile flange |
| Approx. price | $$ (budget-friendly) |
Note: Ferguson now markets this under their "Plus Series" branding rather than "Hillsboro", but it's the same tub. Full model number includes color suffix (WH = white).
Aquatic AcrylX — 6636SMIN
image: aquaticbath.com
| Spec | Value |
|---|---|
| Dimensions | 66" L × 36" W × 18" H |
| Material | AcrylX (reinforced acrylic) |
| Features | Above-the-floor rough, easy install |
| Drain | Right-hand (or left as ac003093-l-to-wh) |
| Water capacity | 52 gal |
Brand correction: Originally listed as "American Standard AcrylX" but this is actually an Aquatic Bath product (same American Bath Group parent as PROFLO/Ferguson, distinct from American Standard). American Standard's own alcove lineup tops out at 60", not 66".
Carver Tubs — ALR6636
image: carvertubs.com
| Spec | Value |
|---|---|
| Dimensions | 66" L × 36" W × 20.5" H |
| Water capacity | 50 gal |
| Material | Acrylic |
| Drain | Right-hand |
How to Choose: Decision Framework
The spec tables above are necessary but not sufficient. For a real selection, weigh these dimensions in priority order:
1. Drain side — eliminates roughly half the options
Hard constraint, not a preference. The drain must match existing plumbing or you're re-plumbing.
- Left-hand drain: Kohler Mariposa, PROFLO Hillsboro
- Right-hand drain: Carver ALR6636, Aquatic AcrylX (also offers left as
ac003093-l-to-wh)
2. Soaking depth — the single biggest comfort factor
Water depth = tub height minus the overflow position (typically 4–7″ below the rim). Rule of thumb:
- ≥14″ water depth: true soaker — shoulders mostly submerged sitting upright
- 11–13″: usable for occasional soaks but feels shallow
- <11″: functional bath, not a soaking experience
For the 4 tubs by external height (* = published, ? = inferred):
- Kohler Mariposa — 21¼″ H → 14″ water depth
*(true soaker) - Carver ALR6636 — 20½″ H → ~13–14″
?(likely true soaker) - PROFLO Hillsboro — 19¾″ H → ~12–13″
?(borderline) - Aquatic AcrylX — 18″ H → ~11–12″
?(shallow)
Data gap: only Kohler publishes water depth directly. The other three are inferred from external height assuming standard overflow placement and could be off by ±1–2″. Worth verifying from manufacturer cut-sheets before final pick.
3. Basin length — for taller users
- ≥48″ basin: comfortable for users 6′0″+
- 44–47″: comfortable up to ~5′10″
- <44″: cramped for most adults
Kohler 48″ (best published). PROFLO 42″ (worst published). Aquatic and Carver basin lengths not published — verify from cut-sheet.
4. Material durability
- AcrylX (reinforced acrylic): Aquatic — best stiffness, least flex underfoot
- Standard acrylic: Kohler, PROFLO, Carver — essentially interchangeable for residential use
5. Price
Kohler runs premium ($$$), PROFLO budget ($$). Aquatic and Carver pricing not yet researched — worth getting Ferguson, Home Depot, and Lowe's quotes before deciding.
Pick by Priority
| If top priority is… | Pick | Caveat |
|---|---|---|
| Deepest soak | Kohler Mariposa K-1229-L | Only one with published 14″ depth; also longest basin |
| Budget | PROFLO Hillsboro | Trade-off: short basin (42″), no published depth |
| Easy install | Aquatic AcrylX | Above-floor rough simplifies plumbing; trade-off: shallowest of the four |
| Durability / stiffness | Aquatic (AcrylX reinforced) | Best resistance to flex; offset by depth concern |
| Right-hand drain required | Carver ALR6636 or Aquatic AcrylX | Kohler / PROFLO eliminated by drain side |
Project Constraints
- Form factor: 66×36 alcove (non-negotiable)
- Drain side: Left-hand (non-negotiable — eliminates Carver, Aquatic)
- Priorities: Durability + style (simple shapes, minimal flourishes)
- Users: 5′6″ and 6′2″ — basin needs to be comfortable for both
- Target water depth: 16–19″ (research shows this exceeds the geometric envelope; see below)
- Budget: No ceiling
- Selected model: Hydro Systems Sydney
SYD6636ATO-WHI-LH
Current Pick: Hydro Systems Sydney SYD6636ATO-WHI-LH
The selected alcove bathtub is Hydro Systems Sydney SYD6636ATO-WHI-LH: 66″ × 36″, white, left-hand drain, acrylic, skirted, with tile flange for the 3-wall alcove condition.
This supersedes the earlier MAAX verification path. Before ordering/release, confirm the exact order code, drain orientation, flange/skirt package, lead time, waste/overflow compatibility, and any installer requirements for setting/leveling the tub.
Depth Reality — Round 2 Research
With form factor and drain side both locked as non-negotiable, the second-round research surveyed Wetstyle, Hydro Systems, Mansfield, Bain Ultra, Americh, MTI Baths, Jacuzzi, MAAX, Oceania, and Hytec. Conclusion: 16″+ water depth is at the absolute geometric edge of this form factor. The deepest available are:
MAAX Exhibit 6636 IF — #106178-L-000-001
| Spec | Value |
|---|---|
| Dimensions | 65⅞″ L × 36″ W × 20″ H |
| Bathing well height | 16¼″ (interior wall-to-floor) |
| Overflow height | ~15½″ (true water depth is drain-to-overflow) |
| Drain | Left-hand (configurable) |
| Material | Acrylic, integrated tile flange (IF) |
| Variants | IFS adds skirt; whirlpool / Aeroeffect jet options also available under same model number |
| Approx. price | $$ to $$$ (~$1,200–$2,000 tub-only) |
Critical caveat: MAAX publishes both figures — well height (16¼″) and overflow height (15½″) — separately. Actual water depth when filled is the overflow figure (~15.5″), not the bathing well height. Confirm with MAAX before ordering — this is the only alcove tub credibly within reach of the 16″ target.
Other near-ceiling candidates (just below 16″)
- Americh Turo TO6636TL — 66×36 alcove, left drain, 15⅞″ interior depth. Premium build (Americh sub-brand of Aquatic Bath, US-made). No image researched yet.
- Hydro Systems Sydney SYD6636ATO-WHI-LH — selected. 66×36 alcove, white, left-hand drain, acrylic skirted tub with tile flange; published reseller specs list 20″ height and about 70 gallons to overflow.
Why deeper isn't possible in this form factor
Alcove external height is constrained to ~20–22″ by the 3-wall enclosure assumption (rim must clear standard wall framing without extreme over-build). The overflow must sit 4–7″ below the rim for code compliance. That math: 22″ exterior − 6″ to overflow ≈ 16″ water depth as the practical absolute ceiling. To go deeper requires changing the form factor (drop-in, undermount, freestanding) — which you've ruled out.
Paths from here
- Pursue MAAX Exhibit 6636 IF — pending one verification call to MAAX to confirm true water depth (overflow height) is ≥16″. If yes: this is the pick. If 15.5″: still the deepest viable option.
- Accept Kohler Mariposa at 14″ — known quantity, premium brand, simpler stocking/lead-time situation. The "safe pick" if the call to MAAX yields no useful gain.
- Relax target to 14–15.5″ — Americh Turo at 15⅞″ splits the difference if MAAX doesn't pan out.
Installation Notes
- Framing: standard 66" alcove rough-in — verify opening is exactly 66" (not 65.5")
- Drain alignment: measure from the finished wall to center of drain hole before buying
- Tile flange: most models have an integral flange on three sides — mount directly against backer board
- Leveling: adjustable feet or mortar bed — never set directly on subfloor without leveling compound
- Access panel: required for drain hookup servicing — plan your alcove access
Material Tradeoffs
Acrylic: Most common. Lightweight, retains heat well, easy to clean. Reinforced cores (e.g., AcrylX) add stiffness.
Enameled steel: Cheaper, heavier, cools faster. Chips can expose steel and cause rust.
Fiberglass/FRP: Budget option. Porous surface can stain; less durable long-term.
Things to Verify Before Buying
- Drain side — left-hand vs. right-hand — must match existing plumbing
- Minimum alcove opening width (some 36" tubs need 36.25" rough-in)
- Water depth if you prefer a deep soak (14"+ is better than 12")
- Integrated flange vs. tile flange — determines waterproofing approach
- Bathewell texture — some prefer smooth, some want slip-resistant texture
Research Status
Initial data gathered from Kohler, Ferguson, Aquatic Bath, and Carver Tubs official product pages.
Still needed:
- Actual water depth vs. stated — manufacturers sometimes overstate
- Long-term durability reviews
- Price tracking across retailers
- Final order release checks for Hydro Systems
SYD6636ATO-WHI-LH: lead time, waste/overflow, install requirements, and drain orientation