How to Test Your Home’s Water for Lead


I read the New York Times article “How New York Gets Its Water” a while ago. The end of the article described how you could order a free lead testing kit.

The EPA offers some guidance on how and when to obtain an in-home testing kit through your local water supplier. In New York City, residents can obtain one at no cost through 311.

For more information, visit, or call the Safe Drinking Water Hotline at 1-800-426-4791.

I read this article in the aftermath of the Flint water crisis and wanted to test my apartment’s drinking water. I filled out the online form, received a package in the mail containing two large plastic bottles, a pre-paid mailing label, and detailed instructions. The instructions said to fill one bottle with water after not using any faucet in my apartment for six hours. I filled the second bottle with water after having run the tap. After dropping the bottles now full of water into a mailbox, NYC’s Nureau of Water Supply sent me the results only week or so later.

We have received the results of your recent tap water lead test. Both samples were under the federal action level of 15 micrograms per liter (μg/L). Your specific results were:

First draw: 0 μg/L 1-2 minute flush: 0 μg/L

What I’m Looking for in a Volunteering Position


My Absolute Requirements

  • Does not require a law degree
    • Although I have thought about getting one just so I can apply for certain volunteering gigs that require one.
  • Does not require me to write code for a significant portion of my volunteer time. I already do that full time and am not looking for more. I am fine giving high level tech guidance, however.

My Preferences

In rough order of preference

  • in-person and local
  • intellectually challenging
  • accommodating of my full time work schedule and personal life
  • 5-10 hours a week
  • months-long to year-long commitment
  • not just a desk job but also field work

Skills I Want to Learn or Improve Upon

In rough order of preference

  • public speaking
  • community organizing and building trust with people who have different backgrounds
  • negotiating and building consensus with and between people who don’t necessarily see eye-to-eye
  • Learning to lobby public officials and organizations
  • learning more about the law or government or various industries
  • investigative reporting

Values of Organizations in which I’ll Thrive

In rough order of preference

  • competence
  • hard work
  • innovation or at least open-mindedness
  • passion and compassion
  • personal responsibility

Skills I Can Contribute

In rough order of ability

  • writing code, creating web sites, general computer stuff (see my github)
  • writing prose such as reports, summaries, and essays (see my blog)
  • analytical and quantitative (I was a math major in college. Now I work at Spotify as a software engineer.)
  • effective at collaborating and working as part of a team
  • good at spoken communication
  • has a knack for establishing rapport and building strong relationships with all kinds of people

A Recent Family Photo


Post-dimsum photo with my parents and maternal grandparents on their weekend visit to NYC.

Southern UK 2016


My trip with my parents to southern UK in March this year. The video includes highlights from London, Cambridge, Seven Sisters, Jurassic Coast, Lyme Regis, and Lulworth Cove.

My First Sailing Class


Last weekend a bunch of Spotify collleagues and I took our first sailing classes at Manhattan Yacht Club in Jersey City. I could get used to this sport. The sun was brutal though. I’ll never get used to that.

Spotify-organized Surfing Trip in Santa Teresa, Costa Rica 2015


In March 2015, about twenty colleagues and I went on a Spotify-organized surf trip to Santa Teresa, Costa Rica for a week of surf lessons. The company, surf, and food were unforgettable. One of Spotify’s social events organizers knew a group of traveling Swedish surf instructors, and helped get a group discount for Spotifiers and their guests. The total cost of lodging, lessons, and daily breakfast and lunch was about $650 for a week.

The relaxing mini-resort where we stayed. It had a pool, lounge areas, and a small cafe.

The best memories I have from the trip are waking up at the crack of dawn every day, grabbing a surf board, and rushing headlong into the water. The sun was gentle in the early morning, but the waves were not. The force and speed of the ocean awed and at times terrified me. I’d paddle like mad to get over waves, but every once in a while, a monster swell would catch me at the worst moment. The crest of the wave would hit me like a hammer and sweep me aside like a match stick. I was taught to cover my head with my arms to prevent the surf board from giving me a concussion. Eventually I learned to do a turtle roll and was able to see a bit ahead of time if a wave would be large or small.

My First Open Water Swimming Event


I visited the southern UK with my parents last March. We visited the coast where I took a photo of the English Channel and posted it on Facebook with the caption, “I’m looking across the English Channel now wondering if I have what it takes to swim across to France. It’s 21 miles across at its narrowest point and the fastest swimmer made it across in a little over seven hours and the slowest one was 27 hours. Average water temperatures in the summer are 14-18 degrees Celsius.”

My high school swim coach Jen saw it and said, “If you are seriously considering, let me know — I have many friends who have done this swim (yes I hang out with weirdos)!”. Let’s start with something a bit more realistic I said. Jen encouraged me to participate in the annual Wayland Three Mile Swim which she organizes. The race takes place in Lake Cochituate, a small body of water in Wayland, Massachusetts which borders my hometown of Wellesley.

So I trained religiously for three months. A couple of days before June 19, I took a bus from New York City back to Wellesley for the open water swim that would start at 7:30AM.

My QCon NYC 2016 Slides - Reach Production Faster With Containers in Testing


Here are the slides from my QCon NYC 2016 talk titled “Reach Production Faster with Containers in Testing.” in various formats. All formats of “Reach Production Faster with Containers in Testing” by David Xia are licensed under a Creative Commons Attribution-ShareAlike 4.0 International License.

More formats here:

My Strange Swimming Experiences


I’ve had some strange swimming experiences.

In 2012 I vacationed on a tiny cay in Belize with a group of college friends. The island was so small that its surface area was probably equal to that of a medium-sized suburban house. An even smaller cay lay a quarter of a mile away with nothing but white sand, coral reefs, and pristine blue water separating them. One day I decided to swim to the smaller island and back. I wore a long-sleeved shirt and pants to not get sunburned and waded into the water with my snorkel mask. I carefully made my way around the sharp corals near the island. Once the water became deep enough, I was surrounded by nothing but deep blue water. I couldn’t see the bottom or any distinguishable shapes in the ocean.

Photo by Todd Quackenbush is licensed under CC BY-NC-SA 3.0

I started seeing ghostly shapes swimming around me. I was scared because I wasn’t sure if I was seeing large fish or if my eyes were just playing tricks on me. I had seen barricudas, rays, and sharks in the water on previous days. I kept swimming. By now I was halfway to the other island. After about 20 minutes I reached shore. The ocean’s depths and creatures made me feel naked and vulnerable and at times like I was going crazy. But I stuck it out and felt strangely triumphant afterwards.

I was six and attending summer camp. The counselors occasionally took us to the Evelyn Kirrane Aquatics Center in Brookline, Massachusetts. One day I stepped into the deep-end of a pool without knowing and began to panic. I tried screaming but couldn’t get my mouth out of the water long enough to take a breath and exhale. I started gulping a lot of water. Luckily, it was a small pool, and I eventually made my way to the wall. I was surprised, however, that I couldn’t signal for help and that no one seemed to notice my distress. Later in life I learned it’s difficult for an untrained person to notice that someone is drowning. Many small children drown each year just a short distance away from their parents.

I lap swim regularly at the Chelsea Recreation Center. Multiple swimmers share a single lane by swimming counter-clockwise. One day, another swimmer was swimming towards me in the opposite direction. According to the rules, we each stuck to our respective right-hand sides. He must’ve been a large person because his wake was bigger than I’m used to. I tilted my head to the side and took a breath just as his wake hit me. Water unexpectedly entered my mouth and nose. I was surprised by how my brain went into auto-pilot emergency mode. I tensed up and began to flail involuntarily. The water and lack of breath was a strong signal to my brain that overrode everything else.

Confessions of a Noob Landlord IV - How to Buy a Co-op Unit


This is a story of I jumped through countless complex bureaucratic, legal, and financial hurdles of Murphy’s Law and emerged with less liquidity and more debt. OK. I’m being facetious, but what happened to me is the easiest and most straightforward way to buy a property. Seriously. The events below transpired in New York City. The buying process may be different in other areas, but the most of the process such as contract of sale and mortgage application is the same across the U.S.

By RKO radio pictures (eBay item photo front photo back) [Public domain], via Wikimedia Commons. Promotional photo of Cary Grant and Myrna Loy for the film Mr. Blandings Builds His Dream House (1948)
  • My mother found an affordable co-op unit for sale while browsing StreetEasy on her iPad during Christmas vacation in 2015.
  • We noticed the listing was made by the seller himself. I emailed him that night.
  • The seller promptly called me. I scheduled a viewing of the unit which is at the top of a six-floor walk-up.
  • My parents and I climbed the six flights of stairs and met the seller who was a nice man named Alan. We walked around and inspected his unit.
  • We asked Alan about the apartment’s condition, the co-op’s financials and rules, the property manager, etc.
  • We sat down with Alan, chatted, and negotiated. My mother pointed out neither party has a broker which is good because brokers take a 6% commission. We felt out Alan on how many offers he’s received and what they are.
  • My mother verbally offered Alan 94% of the listing price. He said he’ll see. My mom seemed confident he’d take it. I was impressed by her ability to knock off over $20K right off the bat.