# FAQ — Water Quality for Coffee

**What TDS level is best for espresso?**
I aim for 75–150 ppm (parts per million) for espresso, which is wider than the often-cited 'golden' 90 ppm—honestly, anything in that range will extract cleanly without over-extracting minerals or tasting flat. Your grind and tamp matter more than hitting a exact number, but staying below 250 ppm keeps mineral buildup off your group head manageable.

**Do I really need filtered water for pour-over coffee?**
You'll get better, more consistent results with filtered water, but it's less critical than with espresso since you're not forcing water through a puck under pressure. If your tap water is soft and tastes fine to you, pour-over is forgiving—but if it's hard or chlorinated, filtration will immediately improve clarity and reduce equipment scaling.

**How often should I replace my water filter?**
It depends on your filter type and starting water quality, but I replace cartridges every 1–2 months or around 40–60 gallons, whichever comes first. Watch for slower flow or taste degradation; if your coffee starts tasting dull or minerally again, that's your cue to swap it out rather than waiting for a set calendar date.

**Is Third Wave Water worth it?**
I've used it for travel and testing, and it's genuinely convenient—you just add a packet to distilled water and dial in your brewing recipe. It's pricier than a home filtration system long-term, but if you're brewing only a few cups weekly or traveling frequently, the consistency and minimal equipment are real benefits.

**Can hard water damage my espresso machine?**
Absolutely—mineral deposits build up inside boilers, group heads, and pipes, reducing heat transfer and eventually causing blockages or heating element failure. Hard water is one of the top killers of home espresso machines, so if you're in a hard-water area, filtration or demineralized water isn't optional, it's maintenance.

**What's the difference between TDS and alkalinity?**
TDS measures total dissolved solids by conductivity—it's a broad mineral count. Alkalinity specifically measures buffering capacity (usually bicarbonate), which affects extraction and how your coffee tastes. You can have high TDS but low alkalinity, or vice versa; both matter, but they tell you different things about water chemistry.

**Should I use distilled or filtered water?**
Distilled water (0 TDS) is too soft and extracts slower, often tasting thin. A quality filter bringing you to 75–150 ppm is better because it removes chlorine and excess minerals while keeping some dissolved solids for proper extraction. If you only have distilled, add a mineral packet like Third Wave Water rather than brewing with pure H₂O.

**How do I measure TDS at home?**
Get a handheld TDS meter (around $15–30)—they're reliable enough for home use. Calibrate it if the model allows, submerge the probe, and note the reading in a few seconds. They're not lab-grade, but they're consistent enough to track whether your filter is working and dial in your brewing water.

**Does chlorine in tap water really affect coffee taste?**
Yes, noticeably. Even at small amounts, chlorine brings a flat or slightly chemical note that's hard to miss in espresso or black coffee. A simple carbon filter removes it almost instantly, and it's often the single biggest immediate improvement people hear when they filter their brewing water for the first time.

**What water should I use for cleaning espresso equipment?**
Use filtered water for backflushing and purging to avoid leaving mineral deposits on your group head and screens. If you're doing deep cleaning with a brush and backflush, even a basic carbon filter helps—you don't need perfect TDS water, but filtered is better than hard tap water, which deposits scale over time.