WMS vs WTS: Which Is the Better Buy in 2026?

Same yardstick, side by side (as of August 2026). Valuation lined up like this is most meaningful for two names in the same corner of the market, which these are. Figures are approximate; verify before investing.

Reading it: WMS is the cheaper of the two on forward earnings, but cheaper is not the same as better. Pair the valuation with growth (how far the forward P/E sits below the trailing P/E) and risk (beta) before you decide.

The metrics above tell you which is the marginally better business. The bigger risk for most people is not picking the slightly worse stock, it is over-concentrating. WMS and WTS share themes, so owning both, or adding either to what you already hold, can quietly push a large share of your portfolio into one bet.

This is the part a generic comparison page cannot answer, because it depends on what you own. Connect your brokerage and Walnut shows your real, combined WMS and WTS exposure, flags overlap with your existing positions, and tells you if adding one would tip you past a concentration you are comfortable with, read-only by default, with your login staying at your broker. Walnut is not an investment adviser.

Advanced Drainage Systems, based in Hilliard, Ohio, makes high density polyethylene and polypropylene pipe along with the fittings, catch basins, chambers and water quality structures that go around it. The business splits into two halves. Stormwater, about 78% of fiscal 2026 sales, moves rainwater off parking lots, highways, subdivisions and farmland. On-site wastewater, roughly 22%, is the Infiltrator business: leach field chambers, plastic septic tanks and advanced treatment systems for homes that will never connect to a municipal sewer. ADS feeds much of this from its own recycling operation, buying post-consumer and post-industrial plastic rather than virgin resin, with Infiltrator alone taking in roughly 75,000 tons a year. In February 2026 the company paid about $1.0 billion in cash for NDS, the residential drainage, access box and irrigation business of NORMA Group. One convention to keep straight: ADS runs on a fiscal year ending March 31, so fiscal 2026 covers the year through March 2026 and fiscal 2027 runs through March 2027.

Full WMS guide

Watts Water Technologies supplies products that manage the flow of fluids and energy into, through, and out of buildings: backflow preventers, pressure regulators, temperature and pressure relief valves, thermostatic mixing valves, leak-detection systems, commercial washroom and hydration solutions, and increasingly smart, connected water controls. It sells across the Americas, Europe, and Asia-Pacific and Middle East and Africa, largely into the plumbing, HVAC, and building-safety channels, where much of the demand is non-discretionary repair, replacement, and code-driven installation.

Full WTS guide

Both fit overlapping themes, but they are not interchangeable. The useful comparison is which set of drivers and risks you want exposure to.

• WMS drivers: Material conversion, not construction growth; Infiltrator carries the margin.
• WTS drivers: Non-discretionary replacement and code demand; Data-center and smart-water tailwinds.

A faster-growing, richer-valued name usually swings harder, so it suits a longer horizon and a higher tolerance for volatility; a steadier, more cash-generative business suits a more conservative or income-minded investor. The honest test is which set of risks you could hold through a drawdown: The end markets are cyclical even if the share gains are not: non-residential construction is the largest single exposure, residential drives Infiltrator through new single family starts in unsewered areas, and agricultural drainage tracks farm income, which has been soft. For WTS, watts is exposed to commercial and residential construction and renovation activity, so a downturn in building spend or higher-for-longer interest rates could pressure volumes.

Pick WMS if you believe its drivers more; WTS if you believe its. Many investors hold both, but since they share themes, that is a concentrated bet, not diversification. Decide deliberately and check overlap. For the full detail, see the WMS and WTS guides.

WMS. The multiple expanded as the mix shifted toward Infiltrator and Allied products, with the market paying for durable margin rather than construction volume. Fiscal 2027 guidance implies 10% to 16% sales growth, though a meaningful slice of that is the first full year of NDS rather than organic demand. Free cash flow of ~$203 million in the June quarter funded a buyback an order of magnitude larger than the dividend, which is how ADS has chosen to return cash.

WTS. Watts posted record first-quarter 2026 results with revenue near $677 million, up about 21 percent year over year, and diluted EPS of roughly $2.97, both ahead of estimates on data-center demand and pricing. For full-year 2026 the company guided to reported sales growth of about 8 to 12 percent, organic growth of 2 to 6 percent, and adjusted operating margin near 19 to 20 percent. At a mid-20s trailing P/E and a sub-1 percent yield, the shares are priced as a quality compounder rather than a value name.

Headline figures (approximate, August 2026): WMS shows revenue (ttm) ~$3.22B, adjusted ebitda (fiscal 2026, year ended march 31) ~$963M, a 31.6% margin, fiscal 2027 guidance ~$3.35B to $3.55B sales, ~$1.00B to $1.05B adjusted EBITDA, p/e (ttm) ~24x on ~$5.88 EPS, ~22x forward; WTS shows revenue (ttm) ~$2.6B, q1 2026 revenue ~$677M (up ~21% YoY), q1 2026 diluted eps ~$2.97 (adj ~$3.04), market cap ~$10B.

WMS and WTS are related but distinct: same themes, different businesses and risks. Neither wins in the abstract; the right pick is whichever thesis you actually believe, sized so you are not over-concentrated in one theme. Walnut can show your combined WMS and WTS exposure against your real portfolio. It is not an investment adviser.