Symptom guide

Why Is My Dog Peeing in the House All of a Sudden?

A house-trained dog that starts peeing indoors may have a medical problem. Causes from UTIs and incontinence to marking and anxiety, and how to fix it.

Updated October 2026 · 7 min read · By the Hushku editorial team · 3 sources

See a vet within 24 hours. Vet within a day or two; same day if straining

Short answer

If a house-trained dog suddenly starts peeing indoors, see your vet first. Urinary tract infections, bladder stones, incontinence, diabetes, kidney disease and Cushing's disease are common medical causes. Once those are ruled out, the usual reasons are incomplete house training, marking, excitement or submissive urination, anxiety, or not getting out often enough. Clean accidents with an enzyme cleaner and never punish.

Key facts

Rule out medical causes first: UTIs, stones, incontinence, diabetes, kidney disease and Cushing's.
Straining with little or no urine is urgent.
Clean accidents with an enzyme cleaner, not ammonia.
Never punish accidents; it makes dogs hide when they pee.

This guide is general information, not a diagnosis. If your pet seems unwell, or you're worried, call your vet.

Overview

Peeing indoors is either a medical problem or a behaviour problem, and the first step is always to rule out a medical cause. A dog that was reliably house-trained for months or years doesn't usually "forget" without a reason.

Watch closely and note: How much urine? Is your dog squatting and straining, dribbling, or lifting a leg on vertical surfaces? Does it happen while sleeping? Is your dog drinking more? Does it only happen when you're out, when visitors arrive, or when your dog is excited? These details point your vet towards the cause.

Straining with little or no urine coming out is urgent, as it can mean a blockage.

Go to a vet now if you see

Straining to pee with little or nothing coming out
Blood in the urine with lethargy, vomiting or pain
Drinking and peeing a lot with vomiting, weakness or not eating

Common causes

1. Urinary tract infection
Needs a vet
Peeing small amounts often, straining, licking the genitals, and sometimes blood in the urine. More common in female dogs.
2. Bladder stones or crystals
Serious
Similar signs to an infection, and stones can block the urethra, especially in male dogs.
3. Incontinence
Needs a vet
Leaking urine while lying down or asleep, common in middle-aged and older spayed female dogs and usually treatable with medication.
4. Drinking more (diabetes, kidney disease, Cushing's)
Serious
Large volumes of urine and accidents because the bladder fills faster than usual.
5. Incomplete house training
Usually mild
Common in puppies, young dogs, newly adopted dogs and after moving house.
6. Urine marking
Usually mild
Small amounts on vertical surfaces, mostly in unneutered males, often triggered by new people, pets or smells.
7. Excitement or submissive urination
Usually mild
Peeing during greetings, play or when reached for, especially in young dogs. Most grow out of it with calm greetings.
8. Anxiety or cognitive decline
Needs a vet
Accidents only when left alone can be separation-related. In senior dogs, forgetting house training can be a sign of cognitive dysfunction.

What you can do at home

Clean accidents with an enzyme-based cleaner; ordinary cleaners leave a smell your dog can detect, and ammonia cleaners smell like urine.
Go back to house-training basics: frequent trips out, especially after sleep, meals and play, and reward toileting outside.
Keep greetings low-key if your dog pees when excited; greet outside or crouch side-on and avoid looming over.
Never punish accidents. It makes dogs afraid to pee in front of you, so they go indoors in secret.
Collect a fresh urine sample in a clean container to take to the vet.
Make sure adult dogs get a chance to toilet at least every 6 to 8 hours, more often for puppies and seniors.

When to see a vet

Any house-trained dog that starts having accidents
Straining, peeing more often, or blood in the urine
Leaking urine while resting or asleep
Drinking more water than usual
Accidents with confusion or night-time restlessness in an older dog

Prevention

Stick to a regular toilet routine
Neutering can reduce marking in male dogs, especially if done before the habit is established
Give older dogs more frequent toilet breaks and easy access to the door

Free tools for this

Sources

We check guides against veterinary sources and update them when guidance changes. How we write and review.

Questions.

Do dogs pee inside out of spite?

No. Dogs don't pee to get back at you. Accidents come from medical problems, anxiety, marking or incomplete training.

Why does my dog pee when I come home?

Excitement or submissive urination. Keep greetings calm, ignore your dog for the first minute, and greet outside where possible.

Can a UTI clear up on its own?

Don't wait to find out. Untreated infections can spread to the kidneys, and similar signs can be caused by stones. Your vet will test a urine sample.

Key facts

Overview

Go to a vet now if you see

Common causes

1. Urinary tract infection

2. Bladder stones or crystals

3. Incontinence

4. Drinking more (diabetes, kidney disease, Cushing's)

5. Incomplete house training

6. Urine marking

7. Excitement or submissive urination

8. Anxiety or cognitive decline