File a lawsuit in Texas and the clock that matters most is not the one you expect. Most plaintiffs ask how many days they have to serve the defendant. The honest answer is that the Texas Rules of Civil Procedure set no fixed number of days for service itself. What the rules do instead is demand diligence: serve promptly, document every attempt, and move to an alternative method the moment the standard ones fail. Drag your feet and you can lose a winnable case, not because the rules gave you a deadline you missed, but because a court decides you did not try hard enough.
The short answer: diligence, not a day count
Unlike federal court, where Federal Rule of Civil Procedure 4(m) gives a plaintiff 90 days after filing to serve the defendant, Texas state court has no equivalent countdown in Rules 99 through 107. A Texas court can dismiss a case for want of prosecution under Rule 165a if the plaintiff fails to prosecute it diligently, and slow service is one of the classic triggers. The practical rule is simple: request citation when you file, hand it to a server the same week, and keep trying until service is complete.
The diligence standard bites hardest near the statute of limitations. Texas courts treat a suit as timely filed only if the plaintiff also serves the defendant within the limitations period or shows diligence in serving soon after it. In Molina v. Gears, decided by Houston’s Fourteenth Court of Appeals in 2018, a plaintiff who filed within the two-year period but did not serve the defendant until more than a year after filing, and more than ten months after limitations expired, lost the case as time-barred. Repeated attempts at the same addresses, with no effort to find a better address or seek alternative service, counted against her. That case is the cautionary tale for every Texas plaintiff: unexplained gaps in your service effort are evidence, and they will be read back to you.
How service starts: citation under Rule 99
Service begins with citation. Under Rule 99(a), when the plaintiff files the petition and requests it, the clerk issues a citation at once and delivers it as the requesting party directs. The requesting party, not the court, is responsible for getting the citation and a copy of the petition served. Ask for citation when you file. Waiting weeks to request it is the first gap a defendant will point to later.
The citation itself tells the defendant what is at stake. Under Rule 99(b), it directs the defendant to file a written answer with the clerk who issued the citation by 10:00 a.m. on the Monday next after the expiration of twenty days after the date of service. That answer deadline is the first hard date in the case, and it runs from service, which is why proving the service date precisely matters so much. Our full breakdown of that clock is in our Texas answer deadline guide.
Who is allowed to serve: Rule 103
Not just anyone can deliver the papers. Under Rule 103, process may be served by a sheriff or constable, by a person authorized by law, by a person at least 18 years old authorized by written court order, or by a process server certified through the Judicial Branch Certification Commission. One hard limit applies to all of them: no person who is a party to the suit, or interested in its outcome, may serve process. A return signed by the plaintiff’s own employee or friend is worthless, and a court will treat the case as though service never happened. Hire a neutral server and keep that problem out of your file.
The two starting methods: Rule 106(a)
Rule 106(a) gives you two methods to start with, and only two. Unless the citation or a court order directs otherwise, the citation must be served by either delivering a copy of the citation, showing the delivery date, and a copy of the petition to the defendant in person, or mailing a copy of the citation and petition to the defendant by registered or certified mail, return receipt requested.
Personal delivery is the stronger choice whenever you have a reliable address. It leaves little room for argument about whether the defendant received the papers. Certified mail works well when the defendant is cooperative or lives far away, but it depends on someone signing for it. If the green card comes back unsigned, or the mail comes back unclaimed, you have not served the defendant. You have documented a failed attempt, which is exactly what you need for the next step.
When standard service fails: substituted service under Rule 106(b)
Substituted service is not a shortcut you can take on day one. Rule 106(b) allows it only after service under Rule 106(a) has been attempted and has failed. The plaintiff must file a motion supported by a sworn statement, made before a notary or under penalty of perjury, listing every location where the defendant can probably be found and stating specifically what attempts were made at that location and why they failed.
If the court is satisfied, it may authorize service by leaving a copy of the citation and petition with anyone older than sixteen at the location named in the statement, or in any other manner, including electronically by social media, email, or other technology, that the evidence shows will be reasonably effective to give the defendant notice. Since the 2020 amendment, Texas courts have approved service by Facebook message, email, and text message in the right circumstances. The key to the motion is the affidavit: vague claims that the defendant “could not be found” will be denied, while a dated log of attempts at specific addresses and times, with notes on what the server found, will usually be granted. Keep that log from the first attempt, not from the week you decide to file the motion.
Proof of service: the return under Rule 107
Service is not complete until it is proved. The server files a return of service with the court, and under Rule 107 it must state when, where, and how service was made, and by whom. For certified mail, the signed return receipt is attached. A return with a missing date, a wrong address, or an unauthorized server gives the defendant a ready-made challenge, and a successful challenge can unwind everything built on that service, including a default judgment. Read the return before it is filed. Fixing a defective return early costs a phone call; fixing it after judgment costs a motion, a hearing, and possibly the case.
Worked example: filing to answer deadline
Take a concrete timeline. A plaintiff files a personal injury petition in Harris County on Monday, October 26, 2026, and requests citation the same day. A process server delivers the citation and petition to the defendant in person on Wednesday, October 28, 2026. Count twenty days from the date of service: that lands on Tuesday, November 17, 2026. The answer is due by 10:00 a.m. on the Monday next after that twenty-day period expires, which is Monday, November 23, 2026. If no answer is on file by that Monday morning, the plaintiff may move for default judgment.
Now change one fact. Suppose the server cannot find the defendant at the home or work address, and certified mail comes back unclaimed. The plaintiff should not wait a month to think about it. Within days, the plaintiff should authorize new attempts at any other known address, then file a Rule 106(b) motion with a sworn statement listing each attempt, each date, and each result. A judge who sees two weeks of documented effort will act fast. A judge who sees three months of silence will ask why the case deserves to stay on the docket.
What happens if you wait too long
Three consequences follow slow service, and they stack. First, the limitations problem: if the limitations period expires while the defendant remains unserved, the plaintiff must prove diligence for every period of delay, and unexplained gaps can end the case, as Molina shows. Second, dismissal for want of prosecution under Rule 165a: a court may dismiss a case that sits idle, and while such a dismissal is usually without prejudice, the limitations clock does not pause during the idle months, so refiling may already be too late. Third, practical cost: refiling means new filing fees, new citation, and a second round of service, all while the defendant knows a suit is coming and may be harder to find.
You may see “120 days” quoted online as a Texas service deadline. Treat that number with care. It does not appear as a statewide deadline in Rules 99 through 107. Some courts set their own scheduling expectations, and some practitioners use it as an internal target, but it is not a rule you can cite to a judge, and it is not a safe harbor you can rely on. Diligence is the standard, and diligence is measured by what you actually did, week by week.
Texas state court vs. federal court
The contrast with federal court is worth knowing if your case could be filed in either system. In federal court, Rule 4(m) gives 90 days from filing to serve, and a court must extend that time if the plaintiff shows good cause. In Texas state court there is no 90-day grace period and no automatic extension. The trade-off runs the other way too: Texas service methods, especially court-authorized electronic service under Rule 106(b), can be more flexible than the federal rules once you have documented failed attempts. Do not import federal assumptions into a state filing. The systems count differently, and the Texas answer clock in particular, with its Monday-at-10:00-a.m. rule, catches federal practitioners off guard. If you need the dates worked out, our free legal deadline calculator handles the counting.
A practical checklist for plaintiffs
Request citation the day you file, and confirm the clerk issued it. Hand it to a qualified, neutral server within days, not weeks. Log every attempt with date, time, address, and result. If mail comes back unclaimed or the defendant dodges personal delivery, start a second round of attempts at other addresses immediately. File a Rule 106(b) motion with a detailed sworn statement as soon as the standard methods have genuinely failed. Read the return of service before it is filed and confirm the date, method, and server are correct. Then calendar the answer deadline from the proven service date, and be ready to move for default if no answer arrives. If you are on the defendant’s side and service looks defective, challenge it early; a late challenge after judgment is a much harder fight, as our guide to what happens when a court deadline is missed explains.
Frequently asked questions
How long do I have to serve a defendant in Texas?
There is no fixed number of days in the Texas Rules of Civil Procedure. You must serve diligently, and if the statute of limitations expires before service, you must be able to account for every period of delay. As a working practice, start service the week you file and never let weeks pass without a documented attempt.
Can I serve the defendant myself?
No, if you are a party to the case or interested in its outcome. Rule 103 bars parties and interested persons from serving process. Use a sheriff, constable, court-authorized adult, or certified process server.
What if the defendant avoids service or cannot be found?
Document your failed attempts under Rule 106(a), then file a Rule 106(b) motion with a sworn statement listing the locations tried and the specific facts of each failure. The court may then authorize leaving papers with someone over sixteen at the location, or service by email, social media, or another method reasonably likely to give notice.
Does certified mail count as service if nobody signs for it?
No. Service by mail under Rule 106(a)(2) requires registered or certified mail with return receipt requested, and the signed receipt is the proof. An unsigned or unclaimed mailing is a failed attempt, not service, but it supports a Rule 106(b) motion.
When is the defendant’s answer due after service?
Under Rule 99(b), the answer is due by 10:00 a.m. on the Monday next after twenty days from the date of service. Service by publication is different: under Rule 114, the answer is due by 10:00 a.m. on the first Monday after forty-two days from issuance of the citation.
What happens if I serve late and the statute of limitations has run?
The defendant will likely raise limitations as a defense and show service came after the period expired. The burden then shifts to you to prove diligence for each period of delay. Unexplained gaps can end the case, even though the petition itself was filed on time. See our overview of Texas court deadlines for how these clocks fit together.
This article is general information about Texas procedural rules, not legal advice. Court rules and local orders change, and individual cases turn on their own facts. Confirm the current rules and any local requirements with the court or a licensed Texas attorney before acting.